Mark Swift, no relation to boy inventor Tom Swift, is an orphan. He is taken care of by his elementary school teacher, Mr Kent, who just happened to invent a working time machine called the Time Retarder. Wow! Kent is wasting his time teaching. This was written and drawn in an era when it seemed okay to expose young children to danger. Mark, who looks about 10, and his “responsible” adult, Mr Kent, plop the Time Retarder down in the middle of a battle between King Darius of the Persians and Alexander the Great. I can only imagine what the Department of Child Services would have done if they had known that.
The feature was created by Jack and Otto Binder for Fawcett’s Slam-Bang Comics. Mark’s time (ho-ho) in comics was limited. Slam-Bang lasted only 7 issues, and after an inventory tale was published in Master Comics #7, Mark and his guardian zipped off to time and place unknown.
Grand Comics Database doesn’t guess at the artist or writer. From Slam-Bang Comics #6 (1940):