 This book also lists a recipe for a, “Tom Collins Gin and Whiskey”, with the only instructions of, “Are concocted in the same manner as a Brandy receipt, substituting their respective liquors.”
In another 1884 book, "Scientific Barkeeping" by E.N.Cook & Co, you can also find a John Collins and a Tom Collins, with the John Collins calling for Holland Gin and the Tom Collins calling for Whiskey.There is a recipe for the Tom Collins in the 1887 posthumous edition of Jerry Thomas' "Bar-Tender's Guide."