There is one aspect of the subject with which I may close this brief paper. I give it without technical explanation; it seems to me an amusing angle.
The theory of stereoscopics—the vision of the twin lenses of the human eyes, set a distance apart to give the perception of depth, of the third dimension—is in itself a subject tremendously interesting, and worthy of anyone's study. I have no space for it here, nor would it be strictly relevant. I need only state that a two-eyed man sees partially around an object (by virtue of the different angles from which each of his eyes gaze at it) and thus sees a trifle more of the background than would otherwise be the case. And this—these two viewpoints blended in his brain—gives him his perception of "depth," of "solidity"—the difference between a real scene of three dimensions and a painted scene on a canvas of two dimensions with only the artist's skill in perspective to simulate the third.
And I cannot refrain from mentioning that in Government tests of the Anti-War Department to determine the perfection of the invisibility of the X-flyers, it was a one-eyed man who proved that they were not always totally invisible!—Ray Cummings.
Thank You
Dear Editor:
I just want you to know this: I am a reader of your truly named Astounding Stories. I really enjoyed reading the "Spawn of the Stars," also "Brigands of the Moon," and I am very glad to hear that we are going to have another of Charles W. Diffin's stories in the next issue—"The Moon Master."—J. R. Penner, 376 Woodlawn Ave, Buffalo N. Y.
"A Wiz"
Dear Editor:
I am only a young girl sixteen years of age but am greatly interested in science. I have no master mind by any means, but have worked out many a difficult problem in school for my science prof.
Your magazine is a wiz. I haven't missed an instalment since it started. Give us more stories like "Monsters of Moyen," and "The Beetle Horde."—Josephine Frankhouser, 4949 Chestnut St., Philadelphia, Pennsylvania.