The German Federal Election System regulates the election of the members of the national parliament, called Bundestag. According to the principles governing the elections laws, set down in Art. 38 of German Basic Law, elections are to be universal, direct, free, equal, and secret. Furthermore, the German Basic Law stipulates that Bundestag elections are to take place every four years and that one can vote, and be elected, upon reaching the age of 18.  All other stipulations for the federal elections are regulated by the Federal Electoral Act. Elections always take place on a Sunday.  Mail votes are possible upon application.
Germans elect their members of parliament with two votes. One vote is for a direct candidate, who ought to receive a plurality vote in their electoral district. The second vote is used to elect a party list in each state as established by its respective party caucus. The Bundestag comprises seats representing each electoral district, with the remainder of seats being allocated to maintain proportionality based on the second vote. Common practice is that direct candidates are also placed on the electoral lists at higher rankings as a fall-back if they do not win their districts.
Constitutional basis
Principles governing the law of elections
According to Article 38, §1 of the German constitution, “the delegates of the German Parliament (Bundestag) […] are elected in a general, direct, free, equal and secret vote.”
These five principles of suffrage are fundamental rights: Any violation of the law can be brought up to the Federal Constitutional Court of Germany in form of a constitutional complaint.
An election is general, if basically every citizen can take part in it: there are no restrictions such as in terms of income, sex, health or any other arbitrary distinctions. But according to the jurisdiction of the Federal Constitutional Court, the prescription of a minimum voting age is compatible with the commonalty of the election.
The exclusion from the active right to vote is also – within narrow limitations – consistent with the Basic Constitutional Law. The exclusion of the passive right to vote is governed by somewhat less strict regulations.

The right to vote is in principle reserved for German citizens and the so-called “status Germans” who are refugees and expelled persons of German descent that settled in Germany. The introduction of a right to vote for foreigners would require an alteration of §20 of the constitution.
An election is immediate if the voters will determines the result directly. The process of an election based on lists compiled by the political parties is, however, compatible with the principle of an immediate election.
An election is considered free if the government does not compel the people's voting decision in terms of content. According to the Federal Constitutional Court's dispensation of justice the principle of a free ballot would not be harmed if a compulsory vote was introduced by the Federal Electoral Law. Electoral advertising at government expense would, however, be incompatible with this principle of electoral law. However, the Federal Government (made up of different political parties) is allowed to conduct public relations if its neutrality is strictly preserved.
Elections are confidential if the voter's decision is not known to anybody else. The German Parliament's voting law even states that no elector is allowed to announce his decision in the polling station. Postal voting is problematic because the secrecy of the ballot is not guaranteed; it has therefore to be taken as an exceptional case. Since the election's more important basic principle of universal suffrage would otherwise be violated, postal votes are admissible.
In principle an election is considered equal if all electoral votes have the same weight. This is for example not the case if constituencies differ considerably in size or if the way these constituencies are politically controlled causes advantages or disadvantages for certain groups of people (gerrymandering).
For electoral lawmaking the most difficult part in terms of constitutional principles is the equality of the election. On the one hand, certain inequalities are unavoidable as the constituencies can not be of exactly equal size and the turnout, too, is not homogenous. On the other hand, the “Überhangmandate” (the "overhang", or extra seats in Parliament a party gets due to gaining more constituency seats than it is entitled to according to Parliament’s proportional seating principle) and a “negatives Stimmgewicht” (negative vote value: an unwanted outcome changing an elector's vote to the opposite of their intended political will expressed with that vote) might influence the “one man, one vote” principle. On 3 July 2008, the Federal Constitutional Court declared the paradox of the “negatives Stimmgewicht”, which is still in effect, to be unconstitutional. For this reason election law has to be changed by 30 June 2011 so that a negative vote value will no longer be possible.
The five percent rule and the basic mandate clause are further strong interventions because they completely reject the influence of entire political streams and their voters in the parliament.
The five percent rule and the overhang (in German: Überhangmandate) are in principle approved by the Federal Constitutional Court and the German jurisprudence.
Suffrage
Right to vote
Suffrage is the civil right to vote. All German citizens over the age of 18 are allowed to vote (Art. 38, para. 2 of the Basic Law for the Federal Republic of Germany), as long as they have lived in Germany for at least a three month continuous period that was within 25 years of the election.[1]
According to Art. 20, para. 2, p.1 all power emanates from the people, that is the people of Germany. Therefore Art. 12 para. 1 of German Federal Electoral Law determines in accordance with constitutional law, that only Germans in the sense of Art. 116, para. 1 are eligible to vote.
Excluded from suffrage are Germans,
who have been deprived of active suffrage by a court in connection with a conviction because of delicts within the fields of treason, compromise of the democratic constitutional state, threat to the external national security, criminal offence against constitutional bodies, as well as criminal offence at elections and ballots, as well as indictable offences against the national defence. (§§ 13 Nr. 1 BWahlG, 92a, 101, 108c, 109i, 45 Abs. 5 StGB)
for whom had been ordered a custodian with contained field of activity through interlocutory injunction (§ 13 Nr. 2 BWahlG)
who find themselves in an asylum according to §§ 63, 20 StGB after having committed an illegal action being criminally incapable because of an order from the criminal court
Eligibility to stand for election
Every German who has reached the age of majority, in Germany 18 years, is eligible to stand for election according to the German Basic Law (article 38, paragraph 2 BL). It has to be remarked that the age of majority can be altered by a simple federal law.
Eligibility to stand for election presupposes the right to vote. However, some German citizens are not permanent residents of Germany and also do not have the right to vote as a German citizen living abroad. They can still be elected if they meet all the other requirements. Yet, people can be deprived of their eligibility to stand for election in certain circumstances. This can happen in the case of an imprisonment of more than a year as is laid down in § 45, subparagraph 1 in the Strafgesetzbuch, the German criminal law.
Election management bodies
The most important election management body is the Federal Returning Officer, appointed by the Federal Ministry of the Interior. Responsibilities include running electoral procedures and chairing the election committee. The leader of the Federal Statistical Office usually holds this office. The Federal Returning Officer is assisted by the electoral committee and the Returning Officers of each Bundesland, the election supervisors and the electoral committee of each constituency as well as the election judges and the managing committee of each electoral ward. They are appointed by the federal government. The other members of the electoral committees are appointed by the Returning Officer.
Election management bodies (EMBs) are institutions of independent, societal self-organisation. In general they are considered to be a sort of federal agency. The Federal Ministry of the Interior, the Supreme Federal Authority, is responsible for the enactment of certain regulations necessary for federal election procedures. However, the Federal Ministry of the Interior does not have the authority to issue directives against the election management bodies.
Scrutiny of elections
Within two months after the federal election (German: Bundestagswahl) any voter can request the scrutiny of elections. According to the established practice of the Federal Constitutional Court (German: Bundesverfassungsgericht) the Committee for the Scrutiny of Elections of the Bundestag, the parliament of Germany, has to reject a request if the distribution of mandates did not change even with the request being granted.
The Committee for the Scrutiny of Elections only makes sure that the Federal Voting Act is implemented properly; it does not deal with possible unconstitutionalities.
If the Bundestag rejects the veto, an appeal to scrutiny of elections can be lodged to the Federal Constitutional Court of Germany within another two months. This appeal has to be joined by 100 eligible voters.
If the veto is successful, the affected member will lose his or her seat in parliament. This member can in turn file a lawsuit against the adjudication.
No appeal to scrutiny of elections against decisions made by the German Bundestag has thus far been successful.
Party structure
Membership
Political parties are required to be membership-based, and the party determines its membership based upon its own bylaws, i.e., the party itself determines who can join, leave, and who is excluded from the party.[2][3] Applications for membership may be rejected without justification, and party bylaws may impose requirements and restrictions on membership, but may not discriminate based on gender, age, religion or ethnicity.[2] All parties have membership fees, which range from 0.5%–4.0% of members' salaries, with reduced fees for low-income members.[2] There is no collective membership.[2] (For example, some countries' labor unions have enrolled its members in parties automatically.)

As parties can reject applications without justification, it's possible to discriminate unofficially.[2] The feminist party Die Frauen even calls all its members women in its bylaws, but claims this term also applies to men.[2]
Governance
Full membership assemblies are used at the local- or district-level, but most parties rely on delegate assemblies (Parteitag or party conventions) above district-level, although all established parties use non-binding full membership referendums for important decisions such as leadership selection.[2][4]
Appointment of candidates
The parties' right to propose candidates
Only parties that have been represented in the Bundestag or a Landtag by at least five delegates since the last election are entitled to propose their own candidates. Other parties have to announce their candidature to the Federal Returning Officer in time, i.e. not later than 90 days before the election day of periodic elections of the Bundestag. They must have been accepted as a party by the Federal Electoral Committee beforehand.
Proposal of candidates for constituencies
The applicants from a party must be elected in a democratic and secret election by an assembly of the party members in a constituency or by a similar board appointed by the party. Every party member entitled to vote is allowed to propose candidates. A candidate does not have to be a member of the party. Since the 2009 German Bundestag elections no member of a different party may be nominated. A written record of the election must be presented to the District Returning Officer, who is responsible for checking the proposal. He points out possible deficiencies and allows remedies to be made.
A county election nomination is only accepted if the nominee belongs to a party that is represented in the Bundestag or the Landtag, or if the party represents a national minority. Otherwise the nominee must have at least 200 signatures from eligible voters in the constituency. It does not make a difference whether the suggestion is handed in by a party or not. Hence a candidate does not need to be supported by a party in a constituency if he has sufficient signatures. The county election nominee must also nominate a person of trust and a proxy who are allowed to release statements to the leader of the county election.
A county election nomination can be recalled either by a joint statement from the two persons of trust or by a statement from the majority of the signataries of the nominee. Through a declaration from the two persons of trust the name of the suggested person can be changed in case the originally suggested person loses his eligibility or dies. Once the nomination is authorised it can neither be recalled nor changed.
If a candidate with a direct mandate dies before election day, the election is cancelled in this constituency. Within the next six weeks, the election is held again, allowing the deceased candidate's party to appoint a substitute candidate. This by-election follows the same rules as the main election. This means that Germans who have come of age in the time between the main and the by-election are not allowed to vote.
Regional lists of parliamentary candidates for election to Federal Parliament
According to the Federal Election Law the nominations for the regional lists basically result from the same system as the constituency nominations. In addition, the order of the regional list is determined by secret election.
The regional list of a party which is neither represented in the Federal Parliament nor in a State Parliament and which does not represent a national minority, requires for its admission the signing of at least one-thousandth of the state's eligible voters, not exceeding 2,000 signatures. For the nomination of confidants and the modification of the regional list, the regulations concerning the constituency nominations are applied correspondingly.
For the calculation of the election threshold, the candidate lists on state level of one party are generally treated as connected, unless the confidants issue a differing declaration to the Federal Returning Officer.
Voting system

The voter has two votes. The federal election system distinguishes between 'first' and 'second' votes. However, these terms refer neither to a hierarchical order of importance of the votes, nor to a logical (chronological) sequence in a valid election process. According to public polls, about 70% (2002) to 63% (2005) of the voters mistakenly thought the first vote to be more important than the second. In some state election systems that have two voting systems modelled after the federal election setup, the votes are called 'vote for person' and 'vote for list'. It is important that both votes have distinct functions.
First vote
The first vote allows the elector to vote for a direct candidate of their constituency, who applies for a direct mandate in the Bundestag (see illustration above, no. 2). Relative majority voting is used, which means that the candidate who receives most of the votes gets the mandate. If the vote results in a tie, the lot drawn by the leader of the regional election is decisive. In this case, the votes for the other candidates are invalid. The primary function of the first vote is to personalize the election. As there are 299 constituencies at the moment, the same number of mandates in the Bundestag are distributed to the elected candidates in each district. However, the first vote does not determine the power of the parties in the Bundestag. For each direct mandate in a Bundesland the party always receives one mandate less from the second vote.
The size and the geographical shape of the electoral constituencies are revised by an electoral committee appointed by Germany's Head of State. The final decision is made by the German Bundestag and can be found in an attachment to the federal electoral law.
Second vote
For the distribution of seats in the German Bundestag, the second vote is more important than the first vote. This second vote allows the elector to vote for a party whose candidates are put together on the regional electoral list. Based on the proportion of second votes, the 598 mandates are distributed to the parties who have achieved at least 5 percent of valid second votes (see election threshold). Since the 1987 German Bundestag elections, the distribution of seats was made according to the Hare-Niemeyer method. Due to a change in the law passed in January 2008, the distribution of seats is now made according to the Sainte-Laguë/Schepers method.
The proportion of seats a party gets in the Bundestag approximately equates to the percentage of votes the party gets in the election. Discrepancies result from overhang and the election threshold. According to §6, para. 1, clause 2 of the Federal Election Law the electors' second votes are not accounted for if those electors give their first votes to a successful and autonomous direct candidate (a candidate who is not nominated by a party). This rule is designed to prevent a double influence on the composition of the Bundestag.
A similar problem occurred at the federal election in 2002. The PDS got two direct mandates in Berlin, but with only 4.0% of second votes they failed to pass the election threshold. The second votes from the electors who voted for those direct candidates counted nevertheless, since in this case both candidates belonged to a party which had handed in a regional list in the respective Bundesland. In its decision of November 23, 1988 (Federal Constitutional Law 79, 161), the Federal Constitutional Court pointed out the relevant loophole in the Federal Election Law to the legislative body. Abolishing the system with first and second votes with the possibility of splitting votes – meaning the elector's option to vote for a direct candidate and for a party independently – would solve the problem automatically.
Abstention and spoilt votes
German parliamentary election law does not have explicit abstention; a ballot paper without markings on it is considered a spoilt vote (separated into first and second vote).
Furthermore, votes are spoilt if the voter’s intention cannot be recognised without doubt, if the ballot paper contains additions or conditions or if it is not an official document. Since the general elections in 2009, only the first vote is spoilt on ballot papers designed for a different constituency as long as they contain the correct regional list for the second vote.
The law of the German federal election does not consider ballot papers which are marked in a way that endangers the confidentiality of the ballot (as, for example, votes marked with an upright cross) as spoilt.
There are further reasons for invalidity concerning the postal vote: Both votes are invalidated if the envelope for the postal vote is empty, if it contains several differently marked ballot papers or if it actually should have been rejected (including also those ballot paper envelopes which differ from the rest in a way that endangers the election secrecy.) In contrast, the votes of voters who die or lose their right to vote before the ballot vote takes place explicitly remain valid.
Invalid votes, equally to non posted votes, have no effect on the result of the poll. Nevertheless their number is officially counted and published.
According to § 4 of the election statistics act, the cause of invalidity is also a census criterion to be mentioned in the official election statistics. The numbers for a total of twelve categories of (partly) invalid ballot papers have been published at last (for the Federal Parliament elections in 2005).
However, it only concerns combinations of the three basic categories “empty or crossed out”, “multiple crosses” and “other causes”, divided into first and second votes. Thus one can hardly deduce the reason for the invalidity; whether it was a matter of purpose, mistake or just ignorance of the voting right. For combinations of invalid and valid votes on a ballot paper, the belonging elected (major) parties have been deciphered as well.
Invalid votes count as non votes in the financing of the parties. The parties do not receive any money for them. As the party's financing is capped and the total sum is regularly being utilised, the discrepancy of valid votes for parties who take part in financing is practically low. A small amount of invalid votes is generally beneficial for parties with above average fund raising (membership fees included) seeing that more money remains in the bonus fund.
Election threshold
Seats in the German Bundestag distributed by regional lists are only given to parties surpassing a five percent election threshold of the federally valid second votes. Alternatively, if a party wins at least three constituencies, a party still gains seats by proportional representation according to the number of second votes they received. Those second votes for parties that meet neither requirement will not be taken into account for the distribution of seats among the rest of the parties. Parties who qualify for proportional representation in this manner are recognized as party groups, as a party must win at least five percent of the vote to qualify as a full parliamentary party, or Fraktion.
The three-constituency rule favours those smaller parties with a regional stronghold. For example the German Party (DP) only won 3.3% of the second vote, but was able to win 15 seats by electing ten members from constituency seats, mostly in the party's heartland of Lower Saxony. In 1957, the DP won 3.4% of the second vote, but elected six members from constituency seats, enabling them to send 17 members to the Bundestag. The three-constituency rule was not used again until 1994, when the PDS won four direct mandates in Berlin, enabling them to send 30 delegates to the Bundestag, despite the fact that they had only 4.4 percent of the second vote.
The clause is meant to minimise the risk of party fragmentation, which partially caused the incapacitation of the Reichstag in the Weimar Republic. The clause is not explicitly mentioned in the constitution as this could cause a conflict with the fundamental principle of equal votes, which states that each vote must have equal weight. However, the general consensus is that the clause is important for the stability of the party system, the capacity of the parliament and the government and overall for the political stability of the state. Thus, a balance must be achieved between the two existing constitutional objectives. The Federal Constitutional Court approves of the threshold clause, arguing that it is allowed to violate a constitutional principle within certain limits, if this is essential to achieve a more important constitutional objective such as the adherence to a principle of electoral law. Because of this, the Federal Constitutional Court allows the threshold clause to be maximally five percent. Thus the legislator has no possibility of increasing it.
National minority parties, such as the SSW, which last ran for parliamentary election in 1961, are now freed from the election threshold due to the fact that under Constitutional Law it is imperative that minorities are protected. This special regulation however does not necessarily apply to a Turkish party, as the Turkish do not yet enjoy the status of a national minority in Germany, unlike the Danish party in Schleswig-Holstein, the SSW, or the Sorbs in Saxony.
Distribution of seats
At first, the number of successful independent direct candidates and the successful direct candidates whose party did not make it into the German Bundestag is taken from the total number of 598 mandates. In the parliamentary election of 2002, both direct candidates were members of the PDS party. Only in the parliamentary election of 1949 were there successful independent direct candidates.
The remaining proportional mandates (596 seats in the election of 2002 and all of the 598 seats in 2005) are distributed among the parties which have obtained at least five per cent, or three direct mandates according to the results of all second votes, in the Sainte-Laguë/Schepers procedure (before the federal election in 2009 it was the Hare-Niemeyer procedure). Afterwards, the obtained proportional mandates of each party are distributed among the candidates’ lists of the Bundesländer, according to the number of their second votes in the respective Bundesländer, by following the same procedure.
The outcome of this procedure shows how many proportional mandates each party has gained in each Bundesland. The candidates who have achieved a seat in the Bundestag can then be identified.
At first, the victorious direct candidates of a party obtain their mandates in a Bundesland. Within the  Bundesländer, in which the number of achieved direct mandates of one party is smaller than the number of achieved proportional mandates, the difference is settled by list mandates i.e. candidates of the Bundesländer list in order of appearance, whereas candidates who have already gained a direct mandate in their district (not matter which Bundesland) are simply left out.
If a party in a Bundesland receives more direct mandates than proportional mandates, all the successful candidates in constituencies gain additional seats in the Bundestag. These seats are called excess mandates. Consequently the Bundestag becomes larger by the amount of additionally gained seats. The other parties receive compensatory mandates. Following the election in 1998 there were 13 excess mandates, 5 excess mandates in 2002 and 16 excess mandates in 2005. In theory it is possible to gain 299 excess mandates. This would occur if all 299 direct mandates are gained by parties who do not receive enough second votes to gain proportional mandates.
If a delegate of the Bundestag who was elected in a constituency in which his or her political party gained a number of excess mandates resigns, his or her seat remains free and cannot be used by the following candidate on the party’s list. At the beginning of the 2002 legislative period the Bundestag consisted of 603 delegates. When SPD delegate Anke Hartnagel died and the head of SPD in Thuringia, Christoph Matschie, resigned, this regulation was enacted. As a consequence, the 15th Bundestag consisted of 601 members.
Classification and assessment of the system

The Bundestag, Germany’s parliament, is elected according to the principle of  proportional representation. In some cases, this system is also referred to as mixed member proportional representation. This, however, is incorrect considering the fact that the mandates gained directly in each federal state are compared to the number of second vote mandates and any differences are compensated with candidates from the party’s list at the state level, if, according to the principle of proportional representation, a party gains more second vote mandates than direct mandates. Therefore, it is more accurate to call it additional member system. However, the so-called mixing election system can be described as parallel voting whereas a certain number of representatives is elected through one of the systems and the other independent representatives are elected through the other system without any mandates being taken over by both of the systems.
Voting for the Bundestag is complicated. In particular, the importance of the second vote is sometimes underestimated.
However, the voting system combines many of the advantages of both the plurality and the proportional voting system. Time has proven that this voting system mainly allows for a proportional distribution of seats, stable governments, change of governments, the possibility of new parties joining the parliament, and in comparison to the Reichstag, the precursor parliament of the Bundestag in the Weimar Republic, it allows for a parliament capable of acting. Presently, the big parties are not considering introducing a majority voting system like they did at the beginning of the first grand coalition in 1966.
However, there has been major criticism of the federal election system. The overhang seats are problematic in the sense that they distort the proportional representation (resulting from the second votes). The Federal Constitutional Court of Germany has found that this distinctive feature is compatible with the legislator’s will of ensuring a regionally balanced composition of the Bundestag. Nevertheless, one consequence of the overhang seats is the paradoxical possibility that a party may receive more seats in the Bundestag by receiving fewer second votes in certain states, or fewer seats if they receive more votes. On July 3, 2008, the Federal Constitutional Court declared the possibility of this so-called "negative vote weight" ("negatives Stimmgewicht") to be unconstitutional,[5] and reforms were implemented in May 2013 that sharply reduced this possibility.
Discussions about the implementation of a majority voting system
By the end of 1955 the CDU/CSU (political union of the parties of the Christian Democratic Union and the Christian Social Union) together with the German party (in German: Deutsche Partei (DP)) brought forward a first draft outlining a possible majority voting system. According to this draft 60 percent of the mandates were supposed to be determined by majority votes and only 40 percent according to proportional representation. Adenauer’s attempt to end the CDU/CSU’s dependence on the FDP (the Liberal Democratic Party) as well as to limit the SPD’s (the Social Democratic Party) prospects of getting elected was unsuccessful.
When the first Grand Coalition (1966–1969) took office, there were strong tendencies within both major parties, CDU and SPD, to abandon proportional representation which had existed/had been applied since the foundation of the German Federal Republic in 1949. Instead, they suggested implementing the majority vote system. These plans were even part of the coalition agreement. The smaller FDP which has no chance of winning the majority in an election district, protested because the implementation of this voting system would have threatened its further existence. Ultimately, however, the introduction of the majority vote system failed because large parts of the SPD were convinced that it would not have meant better prospects of power. Paul Lücke (CDU), Federal Minister of the Interior, resigned from office on April 2, 1968. Since then there have been no more attempts to introduce the majority vote system in Germany.
Forecast
The paradoxes which occur with the largest remainder method are avoided by the recent introduction of the Sainte-Laguë method. The difficulty of "negative vote weight" (where a voter's choosing to vote for a party makes it less likely that that party will gain seats in parliament) still remain possible. But German lawmakers adopted reforms in May 2013 that sharply reduce this possibility, following a July 2008 decision of the Federal Constitutional Court declaring negative vote weight unconstitutional.
History
Election of the first German Bundestag (14 August 1949) – The election system which was valid for the election of the Bundestag in 1949 has been changed significantly in the following decades. Because the Parliamentary Council couldn't agree on a written formulation of the voting system in the Grundgesetz, the Federal Election Law was ratified by the heads of government of the German states. The right to vote was granted from the age of 21, the right to be elected from the age of 25.
The constitutional number of representatives counted 400, plus possible overhang seats and 19 Berlin representatives. The federal territory was divided into 242 electoral districts, each one having one direct candidate being elected according to the relative majority voting, which is still valid. As a result of two CDU overhang seats, the Bundestag of 1949 consisted of 402 representatives.
Each German state formed its own electoral district. Consequently, the number of representatives of a state was determined in advance (excluding overhang seats).Accordingly, the five-percent hurdle and the Grundmandat-clause (one direct mandate was sufficient to join the Bundestag) were valid merely in the federal states.
A single-vote system was used. Using this single vote, the voter elected both a state party list and a direct candidate of the same party from his electoral district. Therefore the voter did not have the possibility to give separate, independent votes for the person or the direct candidate and the party or the list. The voter of an independent direct candidate had in comparison with the two-vote system of today not the possibility to vote a party, with the risk that his vote in a case of unsuccessfulness of the candidate was lost.
In case a direct candidate resigned from the Bundestag, the corresponding electoral district had to hold a reelection. This happened fourteen times the first being the Kulmbach by-election, 1950.
The proportional mandates (Proporzmandate) were allocated using the D'Hondt method which disadvantages small parties. These parties were further disadvantaged because the seats were allocated on a per state basis.
Election of the 2nd German Bundestag (September 6, 1953) – In 1953 for the first time, a law (Bundeswahlgesetz) designed by the German Bundestag was the basis for the federal elections. This law contained some mayor alterations compared to the former election law:
The dual-vote system with the respective possibility of vote splitting was introduced. In order to overcome the election threshold, the party needed to receive a minimum of 5% of all second votes. Although the election threshold was overruled for parties of national minorities, the Südschleswigsche Landesverband (SSW) was not able to re-enter into Parliament. The number of proportional seats increased from 400 to 484, while the 242 electoral districts were maintained. Consequently, the Bundestag is equally represented by seats voted directly as well as via second vote, disregarding additional second vote mandates that have resulted from overhang seats. The number of Berlin's parliament members increased from 19 to 22. In the case of a direct candidate withdrawing from the Bundestag, a new election in his voting district was no longer necessary. Instead, the candidate being next in the state's list of candidates ("Landesliste“) would substitute the candidate.
Election of the 3rd Bundestag (September 5, 1957) – Today's electoral law is basically the same as it used to be in 1957. The two-stage distribution of seats connected with states' canditates lists was introduced, which brought along the problem of negative vote weight. At the same time, the disadvantage of smaller parties was clearly reduced with the D'Hondt method. The Grundmandatsklausel, which says that a party needs at least 5% of the second votes to get any seat in the Bundestag, was modified: from now on at least three direct mandates were needed to overcome this clause. Since the Saarland joined the Federal Republic of Germany on January 1, 1950, five electoral districts were added to the 242 already existing districts and the number of the mandates distributed by proportion was raised from 484 to 494. The absentee ballot was introduced as well.
Election of the 5th Bundestag (September 19, 1965) The electoral districts were rearranged, the number was increased from 247 to 248. Accordingly, the number of mandates distributed by proportion was raised from 494 to 496.
Election of the 7th Bundestag (November 19, 1972) By changing article 38 (2) of the Basic Law in 1970 the voting age was lowered from 21 to 18 and the legal age to be eligible for election was adapted to the voting age, which was 21 at that time. Before that, one had to be 25 to stand for election.
Election of the 8th German Bundestag (October 3, 1976) When the change of sec. 2 BGB (German Civil Code) came into effect on January 1, 1975, the age of consent was lowered from 21 to 18 years. This means that since the election of 1976 citizens have the right to vote and to run for office at the age of 18.
Election of the 11th German Bundestag (January 25, 1987) Since the German federal election in 1987, the largest remainder method, which is neutral towards the size of the parties, has been applied instead of the D'Hondt method. The discrimination of/against small parties when distributing mandates (Proporzmandate) could hereby be completely abolished.
Because of paradoxes that occur in the largest remainder method, the danger of negative vote weight expanded to all federal states, even to those without overhang seats. The voting right for Germans living abroad was introduced during this election.
Election of the 12th German Bundestag ( December 2, 1990) Briefly before the Bundestagswahl of 1990, the Federal Constitutional Court decided that the situation of the recently reunited Germany showed a special case. An election threshold for the entire election district was unconstitutional. For this reason, a party had to receive at least 5% of the second votes either in the old federal territory including West-Berlin or in the new federal territory in order to win seat in the German Bundestag (Lower House of German Parliament). This special regulation was only valid for the elections in 1990.
In the federal states that were formerly part of Eastern Germany, including Berlin, 80 constituencies were added. Because of this, the number of constituencies increased to 328, the number of proportional mandates to 656. Another consequence of German reunification was the abolition of a special regulation for West Berlin. This regulation prescribed that the Berlin City Parliament elected 22 representatives into the Bundestag on the day of the federal election.
Election of the 15th German Bundestag (22 September 2002) – For the election of the Bundestag in 2002, the number of constituencies was reduced from 328 to 299, as was the number of proportional mandates (from 656 to 598).
Election of the 17th German Bundestag (27 September 2009) – For the 2009 election of the Bundestag, the Hare-Niemeyer method was replaced by the Sainte-Laguë/Schepers method. For the first time, parties could no longer nominate candidates who were members of other parties. The circle of Germans living abroad who are entitled to vote was extended.

Erhard H. M. Lange: Wahlrecht und Innenpolitik. Entstehungsgeschichte und Analyse der Wahlgesetzgebung und Wahlrechtsdiskussion im westlichen Nachkriegsdeutschland 1945–1956. Hain, Meisenheim am Glan 1975, ISBN3-445-01152-4
Helmut Nicolaus: Grundmandatsklausel, Überhangmandate & Föderalismus, fünf Studien. Manutius-Verlag, Heidelberg 1996, ISBN3-925678-66-2
Dieter Nohlen: Wahlrecht und Parteiensystem. 4. Aufl., Leske und Budrich, Opladen 2004, ISBN3-8100-3867-9
Wolfgang Schreiber: Handbuch des Wahlrechts zum Deutschen Bundestag. Kommentar zum Bundeswahlgesetz, unter Einbeziehung des Wahlprüfungsgesetzes, des Wahlstatistikgesetzes, der Bundeswahlordnung, der Bundeswahlgeräteverordnung und sonstiger wahlrechtlicher Nebenvorschriften. Heymann, Köln 2002 (7. Aufl.), ISBN3-452-25141-1
Karl-Heinz Seifert: Bundeswahlrecht. Wahlrechtsartikel des Grundgesetzes, Bundeswahlgesetz, Bundeswahlordnung und wahlrechtliche Nebengesetze. Vahlen, München 1976 (3. Aufl.), ISBN3-8006-0596-1

See also
Elections in Germany


Main Page

Herpesviridae is a large family of DNA viruses that cause infections and certain diseases in animals, including humans.[1][2][3] The members of this family are also known as herpesviruses. The family name is derived from the Greek word herpein ("to creep"), referring to spreading cutaneous lesions, usually involving blisters, seen in flares of herpes simplex 1, herpes simplex 2 and herpes zoster (shingles)[4]. In 1971, the International Committee on the Taxonomy of Viruses (ICTV) established Herpesvirus as a genus with 23 viruses among four groups[5]. Latent, recurring infections are typical of this group of viruses, though the family name does not refer to latency.[6] Herpesviridae can cause latent or lytic infections.
At least five species of the Herpesviridae – HSV-1 and HSV-2 (both of which can cause orolabial herpes and genital herpes), varicella zoster virus (the cause of chickenpox and shingles), Epstein–Barr virus (implicated in several diseases, including mononucleosis and some cancers), and cytomegalovirus – are extremely widespread among humans. More than 90% of adults have been infected with at least one of these, and a latent form of the virus remains in almost all humans.[7][8][9]
Nine herpesvirus types are known to infect humans: herpes simplex viruses 1 and 2 (HSV-1 and HSV-2, also known as HHV1 and HHV2), varicella-zoster virus (VZV, which may also be called by its ICTV name, HHV-3), Epstein–Barr virus (EBV or HHV-4), human cytomegalovirus (HCMV or HHV-5), human herpesvirus 6A and 6B (HHV-6A and HHV-6B), human herpesvirus 7 (HHV-7), and Kaposi's sarcoma-associated herpesvirus (KSHV, also known as HHV-8).[10] In total,  more than 130 herpesviruses are known,[11] some of them from mammals, birds, fish, reptiles, amphibians, and mollusks.[10]
Viral structure
Herpesviruses all share a common structure— relatively large, double-stranded, linear DNA genomes encoding 100-200 genes encased within an icosahedral protein cage called the capsid, which is itself wrapped in a protein layer called the tegument containing both viral proteins and viral mRNAs and a lipid bilayer membrane called the envelope. This whole particle is known as a virion.

Herpesvirus lifecycle
All herpesviruses are nuclear-replicating—the viral DNA is transcribed to mRNA within the infected cell's nucleus.
Infection is initiated when a viral particle contacts a cell with specific types of receptor molecules on the cell surface.  Following binding of viral envelope glycoproteins to cell membrane receptors, the virion is internalized and dismantled, allowing viral DNA to migrate to the cell nucleus. Within the nucleus, replication of viral DNA and transcription of viral genes occurs.
During symptomatic infection, infected cells transcribe lytic viral genes. In some host cells, a small number of viral genes termed latency-associated transcript (LAT) accumulate, instead. In this fashion, the virus can persist in the cell (and thus the host) indefinitely. While primary infection is often accompanied by a self-limited period of clinical illness, long-term latency is symptom-free.
Reactivation of latent viruses has been implicated in a number of diseases (e.g. shingles, pityriasis rosea).  Following activation, transcription of viral genes transitions from LAT to multiple lytic genes; these lead to enhanced replication and virus production. Often, lytic activation leads to cell death. Clinically, lytic activation is often accompanied by emergence of nonspecific symptoms, such as low-grade fever, headache, sore throat, malaise, and rash, as well as clinical signs such as swollen or tender lymph nodes and immunological findings such as reduced levels of natural killer cells.

Taxonomy
Group: dsDNA

Order: Herpesvirales

Family: Herpesviridae

Subfamily: Alphaherpesvirinae
Genus: Iltovirus
Gallid herpesvirus 1
Psittacid herpesvirus 1
Genus: Mardivirus
Anatid herpesvirus 1
Columbid herpesvirus 1
Gallid herpesvirus 2
Gallid herpesvirus 3
Meleagrid herpesvirus 1
Genus: Scutavirus
Chelonid herpesvirus 5
Genus: Simplexvirus
Ateline herpesvirus 1
Bovine herpesvirus 2
Cercopithecine herpesvirus 2
Human herpesvirus 1
Human herpesvirus 2
Leporid herpesvirus 4
Macacine herpesvirus 1
Macropodid herpesvirus 1
Macropodid herpesvirus 2
Papiine herpesvirus 2
Saimiriine herpesvirus 1
Genus: Unassigned
Chelonid herpesvirus 6
Genus: Varicellovirus
Bovine herpesvirus 1
Bovine herpesvirus 5
Bubaline herpesvirus 1
Canid herpesvirus 1
Caprine herpesvirus 1
Cercopithecine herpesvirus 9
Cervid herpesvirus 1
Cervid herpesvirus 2
Equid herpesvirus 1
Equid herpesvirus 3
Equid herpesvirus 4
Equid herpesvirus 8
Equid herpesvirus 9
Felid herpesvirus 1
Human herpesvirus 3
Phocid herpesvirus 1
Suid herpesvirus 1

Sub-Family: Betaherpesvirinae
Genus: Cytomegalovirus
Aotine herpesvirus 1
Cebine herpesvirus 1
Cercopithecine herpesvirus 5
Human herpesvirus 5
Macacine herpesvirus 3
Panine herpesvirus 2
Papiine herpesvirus 3
Saimiriine herpesvirus 4
Genus: Muromegalovirus
Murid herpesvirus 1
Murid herpesvirus 2
Murid herpesvirus 8
Genus: Proboscivirus
Elephantid herpesvirus 1
Genus: Roseolovirus
Human herpesvirus 7
Human herpesvirus 6A
Human herpesvirus 6B
Genus: Unassigned
Caviid herpesvirus 2
Suid herpesvirus 2
Tupaiid herpesvirus 1

Sub-Family: Gammaherpesvirinae
Genus: Lymphocryptovirus
Callitrichine herpesvirus 3
Cercopithecine herpesvirus 14
Gorilline herpesvirus 1
Human herpesvirus 4
Macacine herpesvirus 4
Panine herpesvirus 1
Papiine herpesvirus 1
Pongine herpesvirus 2
Genus: Macavirus
Alcelaphine herpesvirus 1
Alcelaphine herpesvirus 2
Bovine herpesvirus 6
Caprine herpesvirus 2
Hippotragine herpesvirus 1
Ovine herpesvirus 2
Suid herpesvirus 3
Suid herpesvirus 4
Suid herpesvirus 5
Genus: Percavirus
Equid herpesvirus 2
Equid herpesvirus 5
Mustelid herpesvirus 1
Genus: Rhadinovirus
Ateline herpesvirus 2
Ateline herpesvirus 3
Bovine herpesvirus 4
Cricetid herpesvirus 2
Human herpesvirus 8
Macacine herpesvirus 5
Murid herpesvirus 4
Murid herpesvirus 7
Saimiriine herpesvirus 2
Genus: Unassigned
Equid herpesvirus 7
Phocid herpesvirus 2
Saguinine herpesvirus 1

The herpesvirus was first isolated from the blue wildebeest in 1960 by veterinary scientist Walter Plowright.[12] The genus Herpesvirus was established in 1971 in the first report of the International Committee on Taxonomy of Viruses (ICTV). This genus consisted of 23 viruses and 4 groups of viruses. In the second ICTV report in 1976 this genus was elevated to family level – the Herpetoviridae. Because of possible confusion with viruses derived from reptiles this name was changed in the third report in 1979 to Herpesviridae. In this report the family Herpesviridae was divided into 3 subfamilies (Alphaherpesvirinae, Betaherpesvirinae and Gammaherpesvirinae) and 5 unnamed genera: 21 viruses were listed. In 2009 the family Herpesviridae was elevated to the order Herpesvirales. This elevation was necessitated by the discovery that the herpes viruses of fish and molluscs were only distantly related to those of birds and mammals. Two new families were created – the family Alloherpesviridae which incorporates bony fish and frog viruses and the family Malacoherpesviridae which contains those of molluscs.[13]
This order currently has 3 families, 3 subfamilies plus 1 unassigned, 17 genera, 90 species and plus 48 as yet unassigned viruses.[14]
Virus naming system
The system of naming herpes viruses was originated in 1973 and has been elaborated considerably since. The recommended naming system specified that each herpes virus should be named after the taxon (family or subfamily) to which its primary natural host belongs. The subfamily name is used for viruses from members of the family Bovidae or from primates (the virus name ending in –ine, e.g. bovine) and the host family name for other viruses (ending in –id, e.g. equid). Human herpes viruses have been treated as an exception (human rather than hominid). Following the host-derived term, the word herpes virus is added, followed by an Arabic numeral (1,2,3,...). These last two additions bear no implied meaning about taxonomic or biological properties of the virus.
Some exceptions to this system exist. A number of viruses' names (e.g. Epstein–Barr virus) are so widely used that it is impractical to attempt to insist on their replacement. This has led to a dual nomenclature in the literature for some herpes viruses. All herpes viruses described since this system was adopted have been named in accordance with it.
Evolution
The three mammalian subfamilies – Alpha, Beta and Gamma – arose approximately million years ago to million years ago.[15] The major sublineages within these subfamilies were probably generated before the mammalian radiation of million years ago to million years ago. Speciations within sublineages took place in the last 80 million years probably with a major component of cospeciation with host lineages.
All the currently known bird and reptile species are alphaherpesviruses. Although the branching order of the herpes viruses has not yet been resolved, because herpes viruses and their hosts tend to coevolve this is suggestive that the alphaherpesviruses may have been the earliest branch.
The date of evolution of the iltovirus genus has been estimated to be million years ago while those of the mardivirus and simplex genera have been estimated to be between million years ago and million years ago.[16]
Immune system evasions
Herpesviruses are known for their ability to establish lifelong infections. One way this is possible is through immune evasion. Herpesviruses have many different ways of evading the immune system. One such way is by encoding a protein mimicking human interleukin 10 (hIL-10) and another is by downregulation of the major histocompatibility complex II (MHC II) in infected cells.
cmvIL-10
Research conducted on cytomegalovirus (CMV) indicates that the viral human IL-10 homolog, cmvIL-10, is important in inhibiting pro-inflammatory cytokine synthesis. The cmvIL-10 protein has 27% identity with hIL-10 and only one conserved residue out of the nine amino acids that make up the functional site for cytokine synthesis inhibition on hIL-10. There is, however, much similarity in the functions of hIL-10 and cmvIL-10. Both have been shown to down regulate IFN-γ, IL-1α, GM-CSF, IL-6 and TNF-α, which are all pro-inflammatory cytokines. They have also been shown to play a role in downregulating MHC I and MHC II and up regulating HLA-G (non-classical MHC I). These two events allow for immune evasion by suppressing the cell-mediated immune response and natural killer cell response, respectively. The similarities between hIL-10 and cmvIL-10 may be explained by the fact that hIL-10 and cmvIL-10 both use the same cell surface receptor, the hIL-10 receptor.  One difference in the function of hIL-10 and cmvIL-10 is that hIL-10 causes human peripheral blood mononuclear cells (PBMC) to both increase and decrease in proliferation whereas cmvIL-10 only causes a decrease in proliferation of PBMCs. This indicates that cmvIL-10 may lack the stimulatory effects that hIL-10 has on these cells.[17]
It was found that cmvIL-10 functions through phosphorylation of the Stat3 protein. It was originally thought that this phosphorylation was a result of the JAK-STAT pathway. However, despite evidence that JAK does indeed phosphorylate Stat3, its inhibition has no significant influence on cytokine synthesis inhibition. Another protein, PI3K, was also found to phosphorylate Stat3. PI3K inhibition, unlike JAK inhibition, did have a significant impact on cytokine synthesis. The difference between PI3K and JAK in Stat3 phosphorylation is that PI3K phosphorylates Stat3 on the S727 residue whereas JAK phosphorylates Stat3 on the Y705 residue. This difference in phosphorylation positions seems to be the key factor in Stat3 activation leading to inhibition of pro-inflammatory cytokine synthesis. In fact, when a PI3K inhibitor is added to cells, the cytokine synthesis levels are significantly restored. The fact that cytokine levels are not completely restored indicates there is another pathway activated by cmvIL-10 that is inhibiting cytokine system synthesis. The proposed mechanism is that cmvIL-10 activates PI3K which in turn activates PKB (Akt). PKB may then activate mTOR, which may target Stat3 for phosphorylation on the S727 residue.[18]
MHC downregulation
Another one of the many ways in which herpes viruses evade the immune system is by down regulation of MHC I and MHC II. This is observed in almost every human herpesvirus. Down regulation of MHC I and MHC II can come about by many different mechanisms, most causing the MHC to be absent from the cell surface. As discussed above, one way is by a viral chemokine homolog such as IL-10. Another mechanism to down regulate MHCs is to encode viral proteins that detain the newly formed MHC in the endoplasmic reticulum (ER). The MHC cannot reach the cell surface and therefore cannot activate the T cell response. The MHCs can also be targeted for destruction in the proteasome or lysosome. The ER protein TAP also plays a role in MHC down regulation. Viral proteins inhibit TAP preventing the MHC from picking up a viral antigen peptide. This prevents proper folding of the MHC and therefore the MHC does not reach the cell surface.[19]
It is important to note that HLA-G is often up regulated in addition to downregulation of MHC I and MHC II. This prevents the natural killer cell response.
Human herpesvirus types
Below are the distinct viruses in this family known to cause disease in humans.[20][21][22]

Zoonotic Herpesviruses
In addition to the herpesviruses considered endemic in humans, some viruses associated primarily with animals may infect humans.  These are zoonotic infections:

Animal herpesviruses
In animal virology, the best known herpesviruses belong to the subfamily Alphaherpesvirinae. Research on pseudorabies virus (PrV), the causative agent of Aujeszky's disease in pigs, has pioneered animal disease control with genetically modified vaccines. PrV is now extensively studied as a model for basic processes during lytic herpesvirus infection, and for unraveling molecular mechanisms of herpesvirus neurotropism, whereas bovine herpesvirus 1, the causative agent of bovine infectious rhinotracheitis and pustular vulvovaginitis, is analyzed to elucidate molecular mechanisms of latency. The avian infectious laryngotracheitis virus is phylogenetically distant from these two viruses and serves to underline similarity and diversity within the Alphaherpesvirinae.[2][3]
Subfamily Alphaherpesvirinae
Genus Simplexvirus
Ateline herpesvirus 1, spider monkey herpesvirus.
Bovine herpesvirus 2 causes bovine mammillitis and pseudo-lumpyskin disease.
Cercopithecine herpesvirus 1, also known as Herpes B virus, causes a herpes simplex-like disease in macaques, usually fatal if symptomatic and untreated in humans.
Fruit bat alphaherpesvirus 1
Leporid herpesvirus 4
Macacine herpesvirus 1
Macropodid herpesvirus 2
Papiine herpesvirus 2
Genus Varicellovirus
Bovine herpesvirus 1 causes infectious bovine rhinotracheitis, vaginitis, balanoposthitis, and abortion in cattle.
Bovine herpesvirus 5 causes encephalitis in cattle.
Bubaline herpesvirus 1
Caprine herpesvirus 1 causes conjunctivitis and respiratory disease in goats.
Canine herpesvirus 1 causes a severe hemorrhagic disease in puppies.
Cercopithecine herpesvirus 9
Cervid herpesvirus 1
Cervid herpesvirus 2
Elk herpesvirus 1
Equine herpesvirus 1 causes respiratory disease, neurological disease/paralysis, and spontaneous abortion in horses.
Equine herpesvirus 3 causes coital exanthema in horses.
Equine herpesvirus 4 causes rhinopneumonitis in horses.
Equine herpesvirus 8
Equine herpesvirus 9
Feline herpesvirus 1 causes feline viral rhinotracheitis and keratitis in cats.
Suid herpesvirus 1 causes Aujeszky's disease, also called pseudorabies.
Genus Mardivirus
Anatid herpesvirus 1
Columbiform herpesvirus 1
Gallid herpesvirus 2 causes Marek's disease.
Gallid herpesvirus 3 (GaHV-3 or MDV-2)
Meleagrid herpesvirus 1 (HVT)
Peacock herpesvirus 1
Genus Iltovirus
Gallid herpesvirus 1 causes infectious laryngotracheitis in birds.
Psittacid herpesvirus 1 causes Pacheco's disease in birds.
Reptilian alphaherpesviruses[28]
Caretta caretta herpesvirus
Chelonid herpesvirus 1
Chelonid herpesvirus 2
Chelonid herpesvirus 3
Chelonid herpesvirus 4
Chelonia mydas herpesvirus
Coober herpesvirus
Emydid herpesvirus 1
Emydid herpesvirus 2
Fibropapilloma associated herpes virus
Gerrhosaurid herpesvirus 1
Gerrhosaurid herpesvirus 2
Gerrhosaurid herpesvirus 3
Glyptemis herpesvirus 1
Glyptemys herpesvirus 2
Iguanid herpesvirus 1
Iguanid herpesvirus 2
Loggerhead orocutaneous herpesvirus
Lung-eye-trachea associated herpesvirus
Pelomedusid herpesvirus 1
Red eared slider herpes virus
Terrapene herpesvirus 1
Terrapene herpesvirus 2
Testudinid herpesvirus 1
Testudinid herpesvirus 2
Testudinid herpesvirus 3
Testudinid herpesvirus 4
Varanid herpesvirus 1
Subfamily Betaherpesvirinae
Genus Proboscivirus
Porcine herpesvirus 2 causes inclusion body rhinitis in swine.
Subfamily Gammaherpesvirinae
Phascolarctid gammaherpesvirus 1
Vombatid gammaherpesvirus 1
Genus Macavirus
Genus Percavirus
Genus Rhadinovirus
Alcelaphine herpesvirus 1 causes bovine malignant catarrhal fever.
Alcelaphine herpesvirus 2 causes an antelope and hartebeest version of MCF
Ateline herpesvirus 2
Bovine herpesvirus 4
Cercopithecine herpesvirus 17
Equine herpesvirus 2 causes equine cytomegalovirus infection.
Equine herpesvirus 5[29]
Equine herpesvirus 7
Japanese macaque rhadinovirus[30]
Leporid herpesvirus 1
Murid herpesvirus 4 Also known as Murine gammaherpesvirus-68 (MHV-68)
Research

Research is currently ongoing into a variety of side-effect or co-conditions related to the herpesviruses. These include:

Alzheimer's disease
atherosclerosis
cholangiocarcinoma
Crohn's disease
chronic fatigue syndrome
dysautonomia
fibromyalgia
Irritable bowel syndrome
multiple sclerosis
labile hypertension
lupus
pancreatic cancer
pancreatitis
pityriasis rosea
Type II Diabetes
Ménière's disease

How many types of herpes virus are there?


Snow country (雪国 yukiguni; also, more prosaically, 豪雪地帯 gōsetsu chitai ["heavy snow area"]) refers to areas in Japan characterized by heavy, long-lasting snowfalls.
The rather poetic snow country(雪国,yukiguni) can refer to any place with heavy or deep snows and is generally understood as a reference to the Sea of Japan side of Honshū (Japan's main island) and the area encompassed by the Japanese Alps, a series of mountain ranges that make up the island's backbone. In its broadest meaning, snow country means the belt along the Sea of Japan from Yamaguchi (in particular, Shimane) in the south to Honshū's northern tip, as well as Sado Island and Hokkaidō. More narrowly defined, it is used to indicate the area from Fukui to Akita Prefecture, but it is most closely associated with part of Fukui and all of Toyama and Niigata Prefectures.
"Heavy Snowfall Zones" refers to places where snowfall and snow cover are severe enough to be a hindrance to the livelihood of inhabitants or the development of local industry. In all, more than half of Japan's land area carries the designation—ten complete prefectures and portions of fourteen others out of Japan's 47 prefectures. Heavy snow areas are eligible for subsidies and other special consideration from the central government to help them cope with the snow (such as for snow removal) and otherwise bring stability to local livelihoods and economies.
The heavy snowfalls of Japan's snow country are caused by moisture-laden clouds bumping up against the mountains along the backbone of Honshū and releasing their moisture under the influence of westerly winds blowing off the continent or down from Siberia. As a result, the region includes some of the world's snowiest spots at the same latitudes, many localities are also frequently visited by avalanches.
Frequently snow is so deep in some places that buildings have a special entrance on their second story; people must remove snow from their roofs to prevent its weight from crushing their homes, and special care is taken to protect trees from the snow's weight. In some towns, people used to tunnel paths to one another's homes, and streets were lined with covered sidewalks to ensure that people could get around. Today in areas where temperatures are high enough to make it practical, many roads are equipped with sprinklers using warm ground water to keep them passable by melting the snow.
The most recent record snows were brought by the blizzards of December 2005–February 2006, when well over 3m (4.5m in one part of Aomori Prefecture) of snow accumulated in many rural areas, and anywhere from  46cm (Tottori) to nearly 1.5m (Aomori) piled up even in several major cities.

One striking feature of Japan's snow country are the snow monsters(樹氷,Juhyō) on Mount Zaō(蔵王山,Zaō-san). Strong wind over the nearby lake fling water droplets which freeze against the trees and their branches, until near-horizontal icicles begin to form.  Falling snow settles on the ice formations, and the end result is a grotesque figure of a tree. The effect of a full forest of such trees gives visitors a ghostly impression.
See also
Mount Zaō
Snow Country, a novel set in Niigata

The content of this article draws on the corresponding Japanese Wikipedia article as well as Japanese Wikipedia articles on the blizzards of December 2005–February 2006 and heavy snowfalls.

 (Seoul Times)


Mauveine, also known as aniline purple and Perkin's mauve, was one of the first synthetic dye.[1][2] It was discovered serendipitously by William Henry Perkin in 1856. It is also among the first dyes to have been mass-produced.[3]
Chemistry
Mauveine is a mixture of four related aromatic compounds differing in number and placement of methyl groups.  Its organic synthesis involves dissolving aniline, p-toluidine, and o-toluidine in sulfuric acid and water in a roughly 1:1:2 ratio, then adding potassium dichromate.[4]
Mauveine A (C26H23N4+X−) incorporates 2 molecules of aniline, one of p-toluidine, and one of o-toluidine. Mauveine B (C27H25N4+X−) incorporates one molecule each of aniline, p-toluidine, and two of o-toluidine.  In 1879, Perkin showed mauveine B related to safranines by oxidative/reductive loss of the p-tolyl group.[5]  In fact, safranine is a 2,8-dimethyl phenazinium salt, whereas the parasafranine produced by Perkin is presumed[6] to be the 1,8-(or 2,9) dimethyl isomer.
The molecular structure of mauveine proved difficult to determine, finally being identified in 1994.[7]  In 2007, two more were isolated and identified: mauveine B2, an isomer of mauveine B with methyl on different aryl group, and mauveine C, which has one more p-methyl group than mauveine A.[8]

skeletal formula of mauveine A
skeletal formula of mauveine B
skeletal formula of mauveine B2
skeletal formula of mauveine C

In 2008, additional mauveines and pseudomauveines were discovered, bringing the total number of these compounds up to 12.[9]
History

In 1856, William Henry Perkin, then age 18, was given a challenge by his professor, August Wilhelm von Hofmann, to synthesize quinine.  In one attempt, Perkin oxidized aniline using potassium dichromate, whose toluidine impurities reacted with the aniline and yielded a black solid, suggesting a "failed" organic synthesis. Cleaning the flask with alcohol, Perkin noticed purple portions of the solution.
Suitable as a dye of silk and other textiles, it was patented by Perkin, who the next year opened a dyeworks mass-producing it at Greenford on the banks of the Grand Union Canal in  Middlesex.[10] It was originally called aniline purple. In 1859, it was named mauve in England via the French name for the mallow flower, and chemists later called it mauveine.[11] By 1870, demand succumbed to newer synthetic colors in the synthetic dye industry launched by mauveine.
In the early 20th century, the U.S. National Association of Confectioners permitted mauveine as a food coloring with a variety of equivalent names: rosolan, violet paste, chrome violet, anilin violet, anilin purple, Perkin's violet, indisin, phenamin, purpurin and lydin.[12]
Laborers in the aniline dye industry were later found to be at increased risk of bladder cancer, specifically transitional cell carcinoma, yet by the 1950s, the synthetic dye industry had helped transform medicine, including cancer treatment.[13][14][15]

Further reading

Rotatable 3D models of mauveine are  using Jmol


An amphibious vehicle (or simply amphibian), is a vehicle that is a means of transport, viable on land as well as on (or under) water.  Amphibious vehicles include amphibious bicycles, ATVs, cars, buses, trucks, military vehicles, boats and hovercraft.
Classic landing craft are not amphibious vehicles as they do not offer any real land transportation at all, although they are part of amphibious warfare. Ground effect vehicles, such as ekranoplans, will likely crash on any but the flattest of landmasses so are also not considered to be amphibious vehicles.

General technical notes

Apart from the distinction in sizes mentioned above, two main categories of amphibious vehicles are immediately apparent: those that travel on an air-cushion (Hovercraft) and those that do not. Amongst the latter, many designs were prompted by the desire to expand the off-road capabilities of land-vehicles to an "all-terrain" ability, in some cases not only focused on creating a transport that will work on land and water, but also on intermediates like ice, snow, mud, marsh, swamp etc. This explains why many designs use tracks in addition to or instead of wheels, and in some cases even resort to articulated body configurations or other unconventional designs such as screw-propelled vehicles which use auger-like barrels which propel a vehicle through muddy terrain with a twisting motion.[1][2]
Most land vehicles – even lightly armoured ones – can be made amphibious simply by providing them with a waterproof hull and perhaps a propeller. This is possible as a vehicle's displacement is usually greater than its weight, and thus it will float. Heavily armoured vehicles however sometimes have a density greater than water (their weight in kilograms exceeds their volume in litres) and will need additional buoyancy measures. These can take the form of inflatable floatation devices, much like the sides of a rubber dinghy, or a waterproof fabric skirt raised from the top perimeter of the vehicle, to increase its displacement.
For propulsion in or on the water some vehicles simply make do by spinning their wheels or tracks,[3][4] while others can power their way forward more effectively using (additional) screw propeller(s) or water jet(s). Most amphibians will work only as a displacement hull when in the water – only a small number of designs have the capability to raise out of the water when speed is gained, to achieve high velocity hydroplaning, skimming over the water surface like speedboats.
History

Some of the earliest known amphibious vehicles were amphibious carriages, the invention of which is credited to the Neapolitan polymath Prince Raimondo di Sangro of Sansevero [5] in July 1770 or earlier, or Samuel Bentham whose design of 1781 was built in June 1787.
The first known self-propelled amphibious vehicle, a steam-powered wheeled dredging barge, named the Orukter Amphibolos, was conceived and built by United States inventor Oliver Evans in 1805, although it is disputed to have successfully travelled over land or water under its own steam.[6]
Inventor Gail Borden, better known for condensed milk, designed and tested a sail-powered wagon in 1849. On testing, it reportedly tipped over 50 feet (15m) from shore, from an apparent lack of ballast to counteract the force of the wind in the sail.[7]
In the 1870s, logging companies in eastern Canada and the northern United States developed a steam-powered amphibious tug called an "Alligator" which could cross between lakes and rivers. The most successful Alligator tugs were produced by the firm of West and Peachey in Simcoe, Ontario.[8]
Until the late 1920s, the efforts to unify a boat and an automobile mostly came down to simply putting wheels and axles on a boat hull, or getting a rolling chassis to float by blending a boat-like hull with the car's frame.[9] One of the first reasonably well-documented cases was the 1905 amphibious petrol-powered carriage of T. Richmond (Jessup, Iowa, USA). Just like the world's first petrol-powered automobile (1885, Carl Benz), it was a three-wheeler. The single front wheel provided direction, both on land and in the water. A three-cylinder petrol combustion-engine powered the oversized rear wheels. In order to get the wheels to provide propulsion in the water, fins or buckets would be attached to the rear wheel spokes. Remarkably the boat-like hull was one of the first integral bodies ever used on a car.[9]
Since the 1920s, many diverse amphibious vehicles designs have been created for a broad range of applications, including recreation, expeditions, search & rescue, and military, leading to a myriad of concepts and variants. In some of them, the amphibious capabilities are central to their purpose, whereas in others they are only an expansion to what has remained primarily a watercraft or a land vehicle. The design that came together with all the features needed for a practical all-terrain amphibious vehicle was by Peter Prell of New Jersey. His design, unlike others, could operate not only on rivers and lakes but the sea and did not require firm ground to enter or exit the water. It combined a boat-like hull with tank-like tracks. In 1931, he tested a scaled down version of his invention.[10]
Recently, Gibbs Amphibians has developed a new type of amphibian, one capable of high speeds on both land and water. The vehicles use a patented hydraulic system to raise the wheels into the wheel wells, allowing the vehicles to plane on water. These vehicles can transition between land and water modes in about five seconds. The first Gibbs fast amphibian is the Quadski, introduced in October 2012. It went on sale in January 2013. Iguana Yachts, a French company created in 2008, has developed amphibious motorboats featuring all-terrain tracks.
Sealegs Amphibious Craft, a three-wheeled amphibious boat designed in New Zealand, has been in production since 2005.

In 2010, a Southern California-based company named WaterCar, set the Guinness World Record for Fastest Amphibious Vehicle, with their prototype, The Python, which reached top land speeds of 204km/h (127mph) and water speeds of 96km/h (60mph; 52 knots).[11] Since then, the company launched their first commercial vehicle, The Panther, which has been featured on ABC's The Bachelor as well as USA's Royal Pains. The WaterCar can do 80mph (129km/h) on land, and 44mph (38 knots; 71km/h) on sea, and can transition from land to sea in less than 15 seconds.[12]
Wheeled
Unarmored
Cycles

An amphibious cycle is a human-powered vehicle capable of operation on both land and water. "Saidullah's Bicycle"[13] uses four rectangular air filled floats for buoyancy, and is propelled using two fan blades which are attached to the spokes. Moraga's "Cyclo Amphibious"[14] uses a simple tricycle frame to support three floaters which provide both the floatation and thrust. The wings on the powered wheels propel the vehicle in a similar way to a paddle wheel.
The SBK Engineering Shuttle-Bike consists of two inflatable floats with straps that allow the carrying of a bicycle with a passenger. The ensemble, when deflated, fits in a backpack for carrying by the cyclist.[15]
Several amphibious cycles have been created by engineering students as university projects.
Gibbs Sports Amphibians Inc. introduced a motorized version of the amphibious cycle that resembles a jet ski on water and motorcycle on land. The model can reach up to 80 mph by land and 45 mph by water.[16]
ATVs

Amongst the smallest non air-cushioned amphibious vehicles are amphibious ATVs (all-terrain vehicles). These saw significant popularity in North America during the 1960s and early 70s. Typically an amphibious ATV (AATV) is a small, lightweight, off-highway vehicle, constructed from an integral hard plastic or fibreglass bodytub, fitted with six (sometimes eight) driven wheels, with low pressure, balloon tires. With no suspension (other than what the tires offer) and no steering wheels, directional control is accomplished through skid-steering – just as on a tracked vehicle – either by braking the wheels on the side where you want to turn or by applying more throttle to the wheels on the opposite side. Most contemporary designs use garden tractor type engines, that will provide roughly 25mph (40km/h) top speed on land.
Constructed this way, an AATV will float with ample freeboard and is capable of traversing swamps, ponds, and streams as well as dry land. On land these units have high grip and great off-road ability, that can be further enhanced with an optional set of tracks that can be mounted directly onto the wheels. Although the spinning action of the tires is enough to propel the vehicle through the water – albeit slowly – outboard motors can be added for extended water use.
In October 2013, Gibbs Amphibians introduced the long-awaited Quadski, the first amphibious vehicle capable of traveling 45mph on land or water. The Quadski was developed using Gibbs' High-Speed Amphibian technology, which Gibbs originally developed for the Aquada, an amphibious car, which the company has still not produced because of regulatory issues.[17]
Cars

Amphibious automobiles have been conceived from ca. 1900, however the Second World War significantly stimulated their development. Two of the most significant amphibious cars to date were developed during World War II. The most proliferous was the German Schwimmwagen, a small jeep-like 4x4 vehicle designed by the Porsche engineering firm in 1942 and widely used in World War II. The amphibious bodywork was designed by Erwin Komenda, the firm's body construction designer, using the engine and drive train of the Kübelwagen. An amphibious version of the Willys MB jeep, the Ford GPA or 'Seep' (short for Sea jeep) was developed during World War II as well. A specially modified GPA, called Half-Safe, was driven and sailed around the world by Australian Ben Carlin in the 1950s.
One of the most capable post-war amphibious off-roaders was the German Amphi-Ranger, that featured a hull made of seawater-resistant AlMg2 aluminium alloy. Extensively engineered, this costly vehicle was proven seaworthy at a Gale force 10 storm off the North Sea coast (Pohl, 1998). Only about 100 were built – those who own one have found it capable of crossing the English Channel almost effortlessly.
Purely recreational amphibian cars include the 1960s Amphicar and the contemporary Gibbs Aquada. With almost 4,000 pieces built, the Amphicar is still the most successfully produced civilian amphibious car to date. The Gibbs Aquada stands out due to its capability of high-speed planing on water. Gibbs built fifty Aquadas in the early 2000s after it was developed by a team assembled by founder Alan Gibbs before the company's engine supplier, Rover, was unable to continue providing engines. Gibbs and new partner Neil Jenkins reconstituted the company and are now seeking U.S. regulatory approval for the Aquada[18]
The Southern California-based company, WaterCar, founded by Dave March, has also built four working amphibious prototypes, one which holds the Guinness World Record for World's Fastest Amphibious Vehicle (The Python). In 2013, March released the company's first commercial vehicle, The Panther. Since its release, WaterCar has been popular in the Middle East, selling to the Embassy of the United Arab Emirates, with six additional vehicles being sold to the Crown Prince of Dubai. The WaterCar has also been sold to tech enthusiasts and residents of Silicon Valley.[19]
Other amphibious cars include the US Hydra Spyder and the Spira4u.[20]

Boats
Some amphibious vehicles, rather than being designed for land transport with the ability to cross water, are designed as water-transport vehicles with the ability to travel on land. The distinction is that the vehicles are designed to be high performing on water, with the land transport ability added to give additional functionality, rather than being the main function. Sealegs Amphibious Craft are an example of this, which are a range of aluminium fabricated boats (mostly RIBs) designed and manufactured in Auckland, New Zealand. These craft can travel up to 39 knots on water, but travel at only 7.5 km/hr on land, showing the preference for water performance in design. Various versions of this type of amphibious boat design have been produced, including the Iguana Yacht (covered in the “Tracked” section below).

Oyster boats
Since 1977, several boat builders in Brittany have built specialized amphibious vehicles for use in the area's mussel and oyster farming industries. The boats are made of aluminium, are relatively flat-bottomed, and have three, four, or six wheels, depending on the size of the boat. When the tide is out the boats can run on the tidal flats using their wheels. When the tide is in, they use a propeller to move through the water. Oyster farmers in Jersey make use of similar boats. Currently, Constructions Maritimes du Vivier Amphibie has a range of models.[21]
Cargo
Trucks and barges

With more than 20,000 units produced, the DUKW was the most successful amphibious truck of World War II. This 31-foot (9.4m) 6x6 truck was used to establish and supply beachheads. It was designed as a wartime project by Sparkman & Stephens, a yacht design firm who also designed the hull for the Ford GPA 'Seep'. During the war, Germany produced the Landwasserschlepper. In the 1950s, the Soviets developed the GAZ 46, BAV 485, and PTS.
During the Vietnam War, the US Army used the amphibious articulated Gama Goat and the larger M520 Goer truck-series to move supplies through the canals and rice paddies of Southeast Asia. The latter was based on a 1950s civil construction vehicle and became the US Army's standard heavy tactical truck before its replacement by the HEMTT. Although the vehicles' wheels were mounted without suspension or steering action, and land speeds over 20mph (32km/h) were ill-advised, its articulated design provided it with good maneuverability and helped it to keep all four wheels firmly in touch with uneven ground. Coupled with its amphibious capability, in the Vietnam War, the M520 Goer developed a reputation of being able to go where other trucks could not.
For taking vehicles and supplies onto the beaches the US used the 1950s designed LARC-V and the huge LARC-LX which could carry 60 tons of cargo.
The British Army used the 6x6 wheeled Alvis Stalwart as their amphibious cargo carrier. In the water vectored thrust water-jet propulsion units drove it along at about 6 knots.
The M3 Amphibious Rig can be used as a ferry or as a floating bridge for trucks and heavy combat vehicles.
Gibbs has also developed other types of fast amphibians including the Phibian, a 30-foot (9.1m) amphibian that is aimed at first responder market, and the Humdinga, a 21-foot (6.4m) amphibian that is capable of traversing extreme terrain.[22]
Armored

Many modern military vehicles, ranging from light wheeled command and reconnaissance vehicles, through armoured personnel carriers (APCs), tanks and amphibious warfare ships, are manufactured with amphibious capabilities.
The French Panhard VBL is a compact, lightly armored 4x4 all-terrain vehicle that is fully amphibious and can swim at 5.4km/h (3.4mph). The VAB is a French fully amphibious APC, powered in the water by two water jets, mounted one on either side of the rear hull (see detail picture above). It entered service in 1976 and around 5000 were produced in many configurations.
During the Cold War the Soviet bloc states developed a number of amphibious APCs, fighting vehicles and tanks, both wheeled and tracked. Most of the vehicles the Soviets designed were amphibious or could ford deep water. Wheeled examples are the BRDM-1 and BRDM-2 4x4 armored scout cars, as well as the BTR-60, BTR-70, BTR-80 and BTR-94 8x8 APCs and the BTR-90 infantry fighting vehicle.
Tracked
Unarmored
Yachts
A French company, Iguana Yachts, has developed boats featuring tracks to assist launch and recovery.[23]
M29 Weasel
The M29 Weasel (Studebaker Weasel), whilst originally designed as a snow vehicle, operated successfully in an amphibious role by the addition of front and rear floats. The basic vehicle will float but its bow is square so the additional floats add stability and load carrying capacity.
Armored

Tracked armored vehicles with amphibious capabilities include those that are intended for use in amphibious assault. The United States started developing a long line of LVT (Landing Vehicle Tracked) designs from around 1940.
Many tracked armored vehicles that are primarily intended for land-use, such as armoured fighting vehicles and armoured personnel carriers nevertheless also have amphibious ability, tactically useful inland, reducing dependence on destroyable and easily targeted bridges. To provide motive power, they use their tracks, sometimes with an added propeller or water jets. As long as the opposite bank has a shallow enough slope for the vehicle to climb out within a few miles, they can cross rivers and water obstacles. An American example is the M113 Armored Personnel Carrier. Soviet examples are the PT-76 amphibious tank, and the BTR-50 and MT-LB APCs based on its chassis.
Some heavy tanks have an amphibious mode in which a fabric skirt is needed to add buoyancy. The Sherman DD tank used in the D-Day invasion had this setup. When in water the waterproof float screen was raised and propellers deployed. The M2 and M3 Bradleys also need such a skirt.
Tanks

At the end of World War I a Mark IX tank had airdrums attached to the side and was tested as an Amphibious vehicle.[24]
By the early 1930s, Vickers had developed an amphibious tank. By using very thin armour, flotation could be achieved without external buoyancy aids. The British Army trialled the Vickers-Carden-Loyd Light Amphibious Tank but did not adopt it for service use. An order was placed with Vickers by the USSR for a small number of tanks. After negotiations to purchase the Vickers tank by Poland failed, they developed their own design the PZInż 130 but dropped the idea of amphibious tanks as obsolete. A pontoon based tank, the L1E3, was produced by Vickers in 1939.
In World War II the British further developed amphibious tanks. The Crusader was trialled with two pontoons that could be attached or removed, the tracks driving the tank in the water. The "Medium Tank A/T 1" was a tank with inbuilt buoyancy some 24ft (7.3m) long and 11ft (3.4m) tall. The Valentine, then the M4 Sherman medium tank were made amphibious with the addition of a rubberized canvas screen to provide additional buoyancy and propellers driven by the main engine to give propulsion. These were DD tanks (from "Duplex Drive") and the Sherman DD was used on D-Day to provide close fire support on the beaches during the initial landings. The Sherman DD could not fire when afloat as the buoyancy screen was higher than the gun. A number swamped and sank in the operation, due to rough weather in the English Channel (with some tanks having been launched too far out), and to turning in the current to converge on a specific point on the battlefield, which allowed waves to breach over the screens. Those making it ashore, however, provided essential fire support in the first critical hours.
Before World War II, The Soviets produced light amphibious tanks called T-37 and T-38. A third serial model, T-40, started production after the beginning of the war. A 14-ton tank, PT-1 was created but was not mass-produced. In addition, an attempt was made to attach pontoons to T-26. While successful, the project was closed due to the high vulnerability and unwieldiness of the construction.

Some light tanks such as the PT-76 are amphibious, typically being propelled in the water by hydrojets or by their tracks. In 1969, the U.S. Army rushed the new M551 Sheridan to Vietnam. This 17 ton light tank was built with an aluminium hull, steel turret, and gun (although the 152mm gun was called a "launcher" at the time), and could swim across bodies of water. The M551 upon arrival in Vietnam began replacing the M48A3 Patton in all cavalry squadrons, leaving only the M48A3 in the U.S. Army's three armored battalions in Vietnam, the 1/77th, 1/69th, and the 2/34th Armor. The Sheridan needed no modifications for river crossings, crewmen simply raised the cloth sides that were tucked inside rubber tubes along the hull's upper edges, raised the driver's front shield which had an acrylic glass window, the driver turned on his bilge pumps, shifted his transmission lever to water operations and the Sheridan entered the water. For newly arrived Sheridans, this might work as engineered. For "war-weary" M551s, the driver's window was often "yellowed" and/or cracked as to obscure his vision, and the rubber tubes that contained the rolled up side sleeves were often cracked and/or frozen into place. The Sheridan could still cross a body of water, but like its swimming cousin, the M113 APC (Armoured Personnel Carrier, also built of aluminium) the river had to be narrow, less than 100 yards (100m). In all cases, the bilge pumps had to be working properly, and even then by the time the Sheridan or the APC reached the other side, water would often fill the insides up to their armoured roofs, spilling through the hatches' cracks and emptying onto the earth once safely ashore. Often a fold down trim vane is erected to stop water washing over the bow of the tank and thus reducing the risk of the vehicle being swamped via the driver's hatch.
During the Cold War, the Swedish Stridsvagn 103 main battle tank carried flotation gear all the time and was, therefore, theoretically, always amphibious.
Multi-unit

The unique capability that distinguishes multi-unit vehicles from single unit ones, is the ability to help each other. According to a 1999 article in Military Parade magazine,[25] multi-unit, all-terrain transport vehicles were first proposed by the British in 1913, and by the 1950s, over 40 types of articulated tracked vehicles (ATVs) were in production. The articulated tracked concept is chosen primarily for its combination of high maneuverability, cross-country abilities, and remarkable load-carrying capacity. In some cases the design is made amphibious, giving them all-terrain capability in the truest sense. Usually, the front unit houses at least the engine, gearboxes, fuel tank(s) and the driver's compartment, and perhaps there is some space left for cargo or passengers, whereas the rear unit is the primary load carrier.
Examples of this concept are the Russian Vityaz, Swedish Volvo Bv202 and Hagglunds Bv206 designs, and the Bronco ATTC of Singapore.
A highly specialised development is the Arktos expedition and evacuation craft, that uses a linkage with two joints to connect the two units, as well as fitting each unit with its own engine, to give each unit enhanced independence of movement.[26]
Deep fording

Some military vehicles are capable of "wading" using waterproof screens to keep the upper hull dry. In World War II the tanks following the Sherman DDs were given waterproofed hulls and trunking was fixed to the engine intakes and exhausts to allow them to come ashore from landing craft in shallow water. The Germans gave their Tiger tank a long snorkel, essentially a long tube on the commander's hatch that allowed it to wade through four metres of water.
The Leopard 2 tank can use a series of rings to create a long tube. This tube is then fitted to the crew commander's hatch and provides air and an escape route for the crew. The height of the tube is limited to around three meters.
The Russian T-90 tank is also able to perform deep fording operations. The Russian snorkel is only a few inches around and does not provide a crew escape path, but it can be stored on the tank.
Some civilian deep wading vehicles achieve their capability by means of legs or stilts to raise the body of the vehicle from its wheels. One example is the Sea tractor, a motor vehicle that can travel through shallow water, with driver and passengers on a raised platform. Another is the Brighton and Rottingdean Seashore Electric Railway, a coastline railway that ran on submerged rails through the shallow coastal waters of the English Channel between 1896 and 1901.
Hovercraft

An air-cushion vehicle (ACV) or hovercraft can travel over land or water supported by a cushion of air ejected downwards against the surface below it. In principle, a hovercraft can travel over any sufficiently smooth surface: solid, liquid, mixed, or anything in between. Large hovercraft, riding on an air-cushion contained by skirts several meters tall, can deal with obstacles 1 to 2 meters in height. The smallest personal hovercraft are nimble enough to follow some rolling of the terrain.
One of the benefits of this type of amphibious craft is the possibility of making them large—the British-built SR.N4 Mk.3 ferries could carry dozens of vehicles. ACVs have a high speed over water (an SR.N4 Mk.1 could do 83 knots (95mph or 154km/h)) and can make the transition between land and water at speed—unlike most wheeled or tracked amphibians. Drawbacks are high fuel consumption and noise levels.
For some military applications wheeled and tracked amphibious vehicles are slowly being supplanted by air-cushioned landing craft. The hovercraft's ability to distribute its laden weight evenly across the surface below it makes it well suited to the role of amphibious landing craft. The US Navy LCAC can take troops and materials (if necessary an M1 Abrams tank) from ship to shore and can access more than 70% of the world's coastline, as opposed to conventional landing craft, which are only capable of landing along 17% of that coastline.
See also
Amphibian aircraft
Amphibious automobile
Float (nautical)
Paddle

Further reading
René Pohl: Mit dem Auto baden gehen. HEEL Verlag, Gut-Pottscheidt Konigswinter 1998, ISBN3-89365-702-9
Ben Carlin, Half-Safe, Andre Deutsch Ltd 1955
Ben Carlin, The Other Half of Half-Safe, ISBN0-9598731-1-2, Guildford Grammar School Foundation 1989

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When was an amphibious vehicle first used in warfare?