400
What is the name of the first Earthly Green Lantern?
Alan Scott.
Green Lantern originally appeared in All-American Comics #16 (July 1940), published by All-American Publications, one of three companies that would eventually merge to form DC Comics. This Green Lantern's real name was Alan Scott, a railroad engineer who, after a railway crash, came into possession of a magic lantern which spoke to him and said it would bring power.