This spectroscope was made by German-born instrument maker Adam Hilger, who opened his premises in London in 1875. This instrument must have been one of the earliest spectroscopes made by Hilger, as it was ordered in the same year. The spectroscope arrived in Sydney the following year; before being sent to Australia it was personally tested by Hilger, who also sent handwritten instructions and diagrams on its use.
By the end of the nineteenth century Hilger had a well established reputation for the making of high quality optical instruments, especially spectroscopes and range finders. Certainly H C Russell, the New South Wales Government Astronomer, felt this particular instrument was important for in his 1878 Report he described it as being the 'most powerful and perfect one in the world at the time of its manufacture'. The spectroscope has three prisms of 64° each so arranged that any power may be obtained from two prisms to eighteen by reflecting the light up to six times through the prisms.
The instrument was certainly well used by Russell and as early as 1878 was being used in conjunction with The Sydney Observatory's Merz 7 1/4-inch refractor. It was also taken to the Blue Mountains where Russell conducted tests to find out whether the performance of the observatory's astronomical equipment was improved in the mountain air.
Perhaps as a result of this use the spectroscope exhibits many signs of wear; the surfaces of most of the tubes are covered with scratches, while the surface of the stand is covered with a heavy patina of cracks. There also appear to have been some modifications made to the instrument, perhaps in an attempt to mount the spectroscope for some other purpose. There is also an original box containing two of the spectroscope's prisms in excellent condition.
In the nineteenth century Adam Hilger Ltd was acknowledged as the world's premier maker of spectroscopes, and the fact that this is one of their earliest instruments lends further weight to the significance of this spectroscope. While the signs of use have affected the appearance of the instrument they are also direct links to the useful life of this instrument at the Observatory.
McConnell, A., Instrument Makers to the World; a History of Cooke, Troughton and Simms, William Sessions, York, England, 1992
De-Clerq, P.R., Nineteenth Century Instruments and their Makers; Rodopi, Amsterdam, 1985
Russell, H., C., Report of Astronomer for 1874 & 1875, New South Wales Government Printer, 1876
Russell, H. C., Astronomical and Meteorological Papers, Thomas Richards, Government Printer, 1880
Russell, H.C., 'Scientific Notes', in Transactions and Proceedings of the Royal Society of New South Wales for the Year 1875, Volume. IX, Thomas Richards, Government Printer, Sydney, 1876
Geoff Barker, August, 2007