切手の大きさは全て一律？
An Act of Congress of March 3, 1845 (effective July 1, 1845), established uniform (and mostly reduced) postal rates throughout the nation, with a uniform rate of five cents for distances under 300 miles (500 km) and ten cents for distances between 300 and 3000 miles. However, Congress did not authorize the production of stamps for nationwide use until 1847; still, postmasters realized that standard rates now made it feasible to produce and sell "provisional" issues for prepayment of uniform postal fees, and printed these in bulk. Such provisionals included both prepaid envelopes and stamps, mostly of crude design, the New York Postmaster's Provisional being the only one of quality comparable to later stamps.
no