This is the second installment of "The Invisible Finite" by Robert A. Wait, a science fiction story published for the first and only time in the May 1929 issue of Amazing Stories.
The story so far:
Professor Moore lectures a class on various efforts to make objects invisible. That afternoon, two graduate students join Moore in his laboratory as he continues to talk about the subject. Finally one of them asks him what they're doing there . . .
* * *
It was a natural and just question that young Murphy asked, and the professor had long expected it. Two young men, bright and intelligent workers in physical chemistry, would indeed be poor scientists if they were content to plod along doing routine jobs for another with no thought as to what was happening or going to happen as a result of their careful labor. The professor sighed as he mentally noted that here again youth would outstrip age, albeit age had contributed the driving force and started the great idea down the swift descent to realization. Dr. Moore knew well that once his purposes were known to the two young men, ideas would flow in voluminous streams from the trained intelligences housed in the rusty-red head of the Irish lad and the dark, bushy head of the Brazilian. Better try to dam up the Mississippi than to stop the flow of thought from two such trained mentalities. No matter, the work would go on and the success would not be his alone. Dr. Moore, as a true scientist, would share in the glory of discovery.
"Jerry, Carlos --"
From this formal salutation the boys recognized a serious turn in the professor's thoughts. They ceased their adjustment work and leaned against the work table in expectant silence.
"You have both worked faithfully and without question at whatever task I assigned you. I want you to know that I sincerely appreciate all you have done. I am about to disclose to you what will make you both famous and prosperous for life. I am an old man. I cannot hope for more than ten, possibly twenty, years of life. The glory will be ours; yours for a long life, mine for a short decade. Your ideas will supercede mine. I will fall more or less into the background. For that I do not care -- only this would I ask of you: always consider me as the origin of your success. With that, I am more than satisfied."
The wondering youths hastened to reassure Dr. Moore that whatever it might be, they were far below him in honor and would always put him first in glory and esteem. The professor smiled a bit wanly and nodded his acknowledgement of the compliment. Behind the smile was a tear, not of self-pity but of sorrow that the human race was so fickle. Despite these vehement reassurances, the professor knew well that it would not be long before the entire proposition would be out of his hands. He would be just "the professor," to be consulted only when the younger men struck a snag in the work. Soit! It was ever thus -- and as a true scientist, the professor prepared to sacrifice his all, that science might gain the knowledge that he possessed.
"My purpose is this work is to produce a material which will have all the properties of solid matter except visibility to human eyes. I have reached the point theoretically where I am certain it can be done. You can see the result of my treatment of the anodes, and our discussion of invisible planes should bring you to see the possibilities that are involved. The proposition is simply this: As you know, matter, if moving rapidly enough and at the same time far enough in one line, becomes invisible to the human eye, allowing the objects on the other side of the matter to become plainly visible. Again, you know from our work that when matter is divided as particles become smaller and smaller in size, we see them with more and more difficulty. We have spoken of grinding a material from large chunks, quite visible, down through the colloidal stage into sub-microscopic particles that are invisible to the eye -- a sort of grinding to invisibility. This has not been found possible as yet, though from my anode treatment of the X-ray machine there, you can get the effect of grey void, the best attempt yet made at invisible colloidal material.
"Of course, all matter is made up of atoms and molecules which are in constant motion, the velocity of which varies according to the particular material; all, however, are extremely rapid in motion. According to our experiment with the spokes of the bicycle, this motion should cause the particles to become invisible. The fact that, though in rapid motion these particles are visible in the aggregate, is explained by the very short length of the path of the motion. All solid and some liquid matter has the particles in it so arranged as to allow each particle to vibrate about a mean point, much as a ball on the end of an elastic cord. Could these particles be induced to stretch these forces and vibrate at enormously larger distances than their natural period, it would seem possible to cause them to become invisible, much as the increase in the speed of rotation of the spokes in a wheel causes the spokes to tend to disappear. Now, could we combine the two theories -- rapid motion in comparatively long paths, and sub-microscopic size in particles -- both of which cause more or less invisibility, we should have an invisible material.
"To me, it is evident that the gases as we know them are invisible, except for color, because of two things: First, the state of subdivision is so minute that we get practically no reflection, or perhaps we might better say that the particles are so small that one will not reflect a light wave --the wave is longer than the particle is large in diameter. Since our second point is that these particles are not held in a mean position by any forces, but travel in Brownian movement in straight random paths until they rebound with perfect elasticity when they collide, thus never losing any velocity, I conclude that the velocity of the particles, coupled with the length of their paths of travel and their very small size, causes them to become invisible to the eye."
The young men had shifted their positions until they were half reclining on the work table, very intent on what the professor was saying. They were absorbing every word with the agility of a mind intent on learning. It was evident that the professor's arguments were convincing the South American lad, and even Jerry's face was glowing in eager anticipation of further explanation of their work.
"That's a very plausible theory to me." Carlos spoke with great enthusiasm, his mobile face animated with an interest even greater than Dr. Moore had hoped to inspire.
"Tell us what all this has to do with these alloy sheets and this mysterious machine you have never explained to us, doctor. Your theory is certainly staggering, but I am a bit incredulous yet. Remember the scientific attitude we learned in freshman years -- 'Never jump to a conclusion because the evidence seems strong.' You yourself have often cautioned students against too hasty acceptance of ideas that are apparently wonderful in possibilities."