One thing is certain and that is that Wednesday, July 3rd, 1940, was SUPERMAN DAY at the legendary World's Fair in Flushing. In the mid-seventies when DC Comics ran a photo feature showing pics from that day, it was alleged that the name of the actor playing Superman had been lost to history. But then someone contacted them and pointed out that it was actor Ray Middleton, then still working on stage, screen (1776) and television (M*A*S*H). So they printed that information.
More recently, someone on the Internet has claimed that, in fact, Middleton was NOT the man of Steel that day but simply a judge in the "Superchildren" contest along with, among others, Frank Buck and Charles Atlas. The piece below, supposedly copied from the next day's NEW YORK TIMES, would seem to confirm that to be the case, indicating that they were unable to ascertain the name of the person playing Superman.
The only thing is...that looks like Middleton as Superman. Compare these various shots from the same time period (some gathered by Terry Beatty). Add to the that various unconfirmed sources that indicate that Middleton would often clim the role later in life as well as sometimes sign autographs with an added 'Superman."
Ray Middleton in 1940 was NOT a major star although, on Broadway at least, he would soon become one. Why, then would he be one of the judges in this contest...unless perhaps he was at the Fair anyway because he had been, in the earlier parade, Superman?
Then I found this which, presuming its legitimacy, would seem to clear up the argument once and for all. This was on eBay. It's a first day issue New York World's Fair envelope postmarked October, 1940 and commemorating the then recent SUPERMAN DAY at the Fair by actually including Ray's name...as SUPERMAN!