Problem in Projection.

Dear Editor:
	May I call Mr. Loomis’ attention to an apparent error in The Talking Hill! Unless my atlas is in grievous error, the Great Pyramid of Gizeh is at 31º 8´ east long., 29º 59´ north lat., which differs considerably from the figures he gave. I was skeptical of the possibility of seeing it from the Mediterranean, but I find it is possible—in fact, theoretically, it can be seen one hundred and twenty-three miles (at least). As for the possibility of hearing the bell note five thousand miles, will you please recall, Loomis, that the upper limit of the sound energy that you broadcast to the four winds so blithely is exactly as much as you put into the original tone. And because of the curvature of the Earth you couldn’t use a focusing device. Think it over.
	And, Mr. Duncan, I don’t agree with your statement re the scientific knowledge of Willlamson. Admittedly, he does not stick to proven fact or verified theory, but does this show he has no scientific knowledge? To me it reveals a fertile imagination, and a soul not too bound by convention. Just what do you seek in a science-fiction magazine?
	In taking issue with Mr. L. S. Kirton you seem to forget that a preference for Campbell or Fort is entirely a matter of personal taste. Incidentally, I think I could prove myself capable of understanding either. I think vou will find the accepted view to be that J. W. Campbell’s articles are intelligently prepared, and are based on modern scientific findings on the whole. Smug superiority is not the true scientific attitude.
	Mr. Bibbero: I think you will find it well established that interplanetary space, regardless of etheric concepts, is not a vacuum, but is comparatively well populated with ions and free electrons.
	Mr. Anderson: A point is 0 dimensional; a line is 1 dimensional; a plane is 2 dimensional; a solid is 3 dimensional.
	A line would always cast a shadow which was a line as long as it was oblique to the direction of propagation of the light. But when the line was parallel to the direction of propagation, its shadow would be a point. Assuming, of course, a point source of light, or a source at infinity. The problem is simply an elementary one in projection.
	Mr. O’Connor: No answer you have received to your question about the irresistible force and immovable mass could be quite so nonsensical as the question itself. By definition, an irresistible force is a force of such magnitude that there exists none other which can successfully oppose it. By definition, an immovable mass is a mass of such magnitude, i. e., possesses such inertia, that it cannot be moved, which implies that there exists no force great enough to move it. Which is to say its inertia (reluctance to change of position) is infinite. It is equivalent to saying, “What happens when an irresistible force meets an irresistible force?”
	From the definition, you see that the existence of two such quantities simultaneously is contradictory, else there would exist a second force capable of successfully resisting the first. But if that were so the first would not have been irresistible, which is a contradiction, since we expressly stated at the outset that it was irresistible. Hence the second could not have been irresistible.—William H. Pell, 2201 University of Kentucky, Lexington, Ky.