A later ad said if you signed up enough friends and formed a club, you could receive a visit from Captain Battle himself. Promo ad from Silver Streak Comics #16, November 1941.
The inside front cover from Miracle Comics #1. I blogged about this advertisement several years ago. We've no way to know, but I'd be willing to bet that the ray gun was about the size of a bracelet charm or a gumball machine toy.
Check out the streamlined buildings! This cover is action-packed and great fun -- moreso than the contents. Masked Angel is a fellow in a tuxedo and domino mask, Scorpion is just a guy -- no costume or anything, and Blanda Jungle Queen was simply dull. If I'd been nine years old in 1940 and paid a dime for this, I'd have felt a bit gypped. Miracle Comics #1, February 1940, with cover art by Ed Kressy.
There were a couple of "Science Comics" by different publishers during the 1940's. One was actually about science. The other one was...well, this. The only science evident here is the result of an experiment to see what happens when a woman doesn't eat for a month or two. Fox Features' Science Comics #2, March 1940. Surprisingly, the cover is by Lou Fine -- a far cry from his best work.
Not a Golden Age cover, but still a fabulous example of Good Girl Art. It's the cover of Jonny Quest #5, 1986, by the late, great Dave Stevens (of Rocketeer fame). I have the whole run of the 80's Jonny Quest books in my collection.