I haven't had the time to explore it yet, but the magazine Popular Mechanics is available now through Google Books -- all of the issues from January 1905 on. What's great is that intact magazines were scanned for this project, including covers and ads. This is not trivial, in that many magazines preserved in libraries were stripped of such material when being bound for posterity. Ironically, those doing the excision must have felt that they were cutting out the nonessential, which many researches now find essential indeed. Unfortunately, one can't always make good the loss by referring to microfilmed records of old periodicals, since nearly all of the films were made from bound library copies.
Getting back to Popular Mechanics, however, let me note that the link above is great for browsing, or for searching individual issues, but if anyone is planning on doing a comprehensive search on, say, "Vacumatic", the Google Books Advanced Search function is what is needed.
PS Interestingly enough, without any additional search terms, "Vacumatic" turns up 193 listings, starting with a "Vacu-matic" carburetor from 1935 on. "Parker" and "pen" give better results, all quite early.