While searching for low frequency, high current amplifiers I cam across the following two articles in an issue of Popular Science from 1944 on Google Books. The first is a great article on how oscillators work and what they are used for. The second article is on iron. The great part is that there's a "try it at home" recipe for thermite and a primer on the first page of the article. They definitely know how to grab and hold a reader's interest. Finally, check out the whole issue at the link above. There are lots of other cool things like two color pages containing Disney created fighter squadron insignia, (some of which are shown above). For the moment, the Google Boooks embed code below has gone loopy, so follow the links to the magazine articles.