The Ghost, aka George Chance, was a magician trained in India who used his legerdemain and mystic knowledge to enhance his detective work, convincing his nemeses that he was an actual ghost. He first appeared in Jan 1940 in the pulp fiction magazines as the title character of The Ghost Super-Detective, a series that lasted for seven issues with two renamings (The Ghost Detective with the fourth issue in Fall 1940, followed by Green Ghost Detective for the fifth issue in early 1941). Later, he had additional stories in Thrilling Mystery, but no time travel. But when George Chance made the leap to comic books, his second story (“The Ghost Strikes Again” in Thrilling Comics 4, May 1940) introduced the evil Professor Fenton and his time machine. From then until Thrilling Comics 52 (Feb 1946) had regular adventures, mostly with Fenton:

Before it became a war comic, the first twelve issues of ACG’s Operation Peril included a regular series about Dr. Tom Redfield and his rich fiancé, Peggy, who buy some of Nostradamus’s papers and discover that he’d designed a time machine.

I haven’t found definitive information on the creators of this series. Several sites name ACG editor Richard E. Hughes as the writer; some places speculate that it was drawn by Ken Bald, but Pappy’s Golden Age Blog indicates that a reader names Lin Streeter as the actual artist, and Pappy agrees.