Per information from the NY Superior Court hearing, Ace art director, Fred Gardener, stated that Patrick "Pat" Lamar's studio provided all of the artwork for this issue, as well as script, lettering, and coloring.
The on-sale date is from the publication date recorded in the Catalog of Copyright Entries, Part 2, Periodicals, 1940, New Series, Vol. 35, No. 3.
The inside-front cover.
Vulcan is the descendant of the Roman god of Fire and is able to control all forms of fire, flame and heat. He is able to use these powers for fire projection, as well as flight and the protection from fire. He also possesses superhuman strength.
Adapted from "The Frozen Phantom" by Lester Dent. The hero's name is changed, but not the villains. Some notes info by Will Murray (Per Sandell, 2005-01-22). Original story was published in Western Trails, April 1933
Adapted from the Secret Agent X-story "Octopus of Crime" by Paul Chadwick, Sept 1934.
Script adaptation per Jerry Bails in the Who's Who, added by Craig Delich.
Pencil credit revised from Harry Lucey ? to ? by Craig Delich. The Who's Who doesn't indicate that Lucey worked on this feature for Ace, nor is there any extant evidence that proves that he did.
Art credits by Craig Delich, per Mark Carleson-Ghost in Alter Ego #144 (January, 2017).