Definition of "footwarmer"

Sturrock records that he found hot-water footwarmers in use on the Northern Railway of France in about 1857, and that he was so impressed with the extra comfort obtained from this simple device that he obtained permission from the French authorities to bring one to England. A dozen similar, but smaller footwarmers were made at Doncaster, without official sanction, and placed in the coaches of a train conveying some of the directors to London. Sturrock was taken to task by the chairman for having incurred this unauthorised expenditure, but before he left the meeting, the directors had ordered 200 footwarmers for public use.

1948 January and February, “Memoirs of Archibald Sturrock”, in Railway Magazine, page 47

stoves warmed and clarified the air, and there were always hotwater bottles and footwarmers for cold nights.

2002, Colin Jones, The Great Nation, Penguin, published 2003, page 357