Mel at a Convention

Dr. Vreeland Heiss writes: [AIR 16:2]

My uncle came into possession, shortly after the world war in the 1940s, of this photo which shows Mel, the little man who always appears in your pages. I have drawn the customary arrow to indicate his location in the image. Perhaps your readers can help me identify the date and location of this event which I believe to be a convention or meeting of a scientific organization or perhaps of a political party, or maybe of some railroad employees. Your readers, too, can help me, I hope, narrow down exactly which of the persons here is Mel—I have confined the possibilities to one of the six or so people indicated near the very tip of the arrow. We wonder if the man in the middle is making a rabbit imitation with his fingers, and if he is, we wonder why.