evidence: This one volume index is the specially prepared companion to the microfilm copies of the U.S.'s early, unnumbered patents (i.e., those that were issued from 1790 to 1836). It lists these earliest patents by patent class, then alphabetically by invention title and by issue date. These lists give the specific microfilm reel number where the full text, specifications, and drawings are located. [...] A listing of the earliest patents issued by the U.S. Patent Office prior to 1836. Sometimes referred to as the "X" patents from the numbering system applied to them on a retrospective basis. This resource lists the patents in date order, with name and type of invention. Copies available to download here: [...] In addition, U.S. patents are available from the European Patent Office's Espacenet website, and from Google Patents as well as various other free and fee-based online resources.