John Collins

A John Collins is a long drink of London dry gin, lemon juice, sugar and carbonated water, which was attested in 1869, but may be older. It is believed to have originated with a headwaiter of that name who worked at Limmer's Old House in Conduit Street in Mayfair, which was a popular London hotel and coffee house around 1790–1817. It is essentially a variant of Tom Collins, evidently a latter name for the same drink. The John Collins is a Collins cocktail—that is, a long drink stirred with ice and topped with soda—made from London dry gin, lemon juice, sugar and carbonated water. A recipe for a John Collins is featured in the Steward and Barkeeper's Manual of 1869:

Source: Wikipedia