"Then What Should You Stop Doing, Ray?" in The Atom #35, by Gardner Fox (writer), Gil Kane (penciler), Sid Greene (inker), Gaspar Saladino (letterer), and ??? (colorist)
One of the holdovers from my father's collection. I was positive I had issue #29, where the Atoms of Earths 1 and 2 team up to fight The Thinker, but it's gone missing somewhere along the way.
The time travel adventure is the second of two stories in this issue, the other involving the Atom trying to stop some crooks who are stealing random collectible crap for an obsessive compulsive genius so he'll plan out their heists for them. Ray gets temporarily defeated in that story by a vacuum cleaner, but it did teach me that his primary size control device is in his belt, not his gloves. Even though he uses the controls in his gloves all the time. OK Ray, whatever.
The time travel story is mostly a history lesson about what its title suggests, although there's also a bit in there where Ray defends the colonel from some hoodlums calling themselves "Mohawks", and Ray musing that since fisticuffs haven't been invented yet, he should have an easy fight against these guys. Sure, that's what'll make it a breeze, not the fact these guys have no idea what to do against a tiny opponent they can't even see. Feels like Gardner Fox read that somewhere and was like, "That's goin' in a story!' At least I learned something, and it gave Gil Kane more opportunities to show people getting socked in the face, which he is very good at drawing, as I'm sure most of you know.

