I have 'The Complete National Geographic' 1888 thru 1998 on CD's. Just for fun I searched for Hamilton and Elgin watch ads. Between Feb. 1908 and Jan.
1990 Hamilton posted 395 ads. Between Sept. 1914 and Apr. 1950 Elgin posted 153 ads.
I also found 6 ads. each from South Bend and Illinois from the teens and 20s.

Joe