Rose's lime juice and nothing else".
As with many classic drinks, both the gimlet and Rose's lime juice have nautical pasts. In the eighteenth-century, the British navy was eager to find ways to fend off scurvy and citrus was the answer. Captain James Cook provided his crewmen with a daily ration of lemon or lime juice, both of which combined very nicely with their daily gin ration. The alcohol preserved the juice and the juice improved the flavor. This is also, of course, how British sailors came to be known as "limeys". In 1867, Lauchlan Rose patented a method of preserving lime juice with sugar rather than alcohol. Not coincidentally, he opened his first factory for the product right by the docks in Leith, Scotland.