This is the third installment of "The Invisible Finite" by Robert A. Wait, a Gernsback Era 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, and he answers that he has invented an invisibility process . . .
* * *
Young Murphy uttered the latter part of his not too enthusiastic comment in half apology for even seeming to dispute Dr. Moore. He was a hard-headed young fellow, but, as with most Irish people, as lovable as could be found. It was only because he was a good scientist that he was skeptical. Early in his career he had learned that skepticism was not a vice -- more of a virtue, ofttimes preventing false conclusions based on insufficient evidence.
"These sheets that we've been working on are an alloy of gold. You know that many alloys of gold are extremely hard and that some alloys are beautiful in color. This alloy has both gold and uranium in it. The uranium is present in only minute quantities. It is present because of its radio-active properties. This seems to promote the activity I am after. The polishing process which we go through is to cover the sheets of alloy with a thin coat of the colloidal platinum like that I used on the anodes of our Z-ray machine. I call it Z-ray because I really know no other name for the particular ray I produce with the machine. The oily liquid we use is a chloro-platinate which I reduce to platinum, catalytically, in the presence of some gaseous reducing agent such as hydrogen or carbon monoxide. This leaves the freed platinum in the sub-colloidal state. The oil forms a coating only ten or twenty molecules thick. With the very fine state of division of the platinum, we obtain the hazy impression of grey void noticed on the ends of the anodes."
"I can see that easily," interrupted Manoras, "but I don't see that this coating will make the alloy pass the light rays reflected by other objects."
"No, that is true; it won't pass light rays -- yet. Bring that black enameled cabinet in the fume-hood. We'll just start this to going and explain as we do it." The professor turned to the chemistry table.
Jerry strode to the fume-hood and carefully extricated the indicated enameled cabinet from the maze of apparatus. True to form, the professor of science had apparatus strewn from end to end of the two-room suite of laboratories.
Dragging a large steel cylinder across the floor, the professor directed manipulations so that he could connect the steel cylinder directly to the top of the cabinet, placing a Bunsen burner beneath so as to heat the sheet iron bottom of the cabinet.
Deftly Dr. Moore removed the clamped stack of treated alloy foil from its temporary housing under the quartz covering and placed it in the cabinet. Carefully closing the black doors and snapping the catches, the professor waved the boys aside.
"The treated sheets are in a gas-tight, heated compartment. You will note the jet at the bottom of the cabinet. We fill this cabinet with carbon monoxide from this cylinder, and since the gas is very slightly lighter than air, we may force the air out through the jet, and by testing frequently with the flame, determine when carbon monoxide has completely filled the cabinet. Since carbon monoxide burns with a bright blue flame, we can easily determine when the gas is escaping from the jet. This we ignite and allow to burn, both to be sure of a constant flow of the reducing agent and to prevent our own asphyxiation from its deadly effect on the hemoglobin of our blood."
The genial old man suited actions to his words and after a few trials, a bright blue flame shot out in a three-inch jet from the base of the cabinet. The jet was so arranged as to burn the gas under the cabinet.
"The burning jet of the escaping gas furnishes enough heat to keep the reaction going after we start it with a Bunsen burner, as you see I am doing. Please move that Roentgen ray machine over here and direct a stream of X-rays through the cabinet."
The two youths quickly had the bulb in action, the anode red with the impact of the electron stream striking upon it.
"The gas I am about to entrain in the stream of carbon monoxide is my catalyst. It is only necessary to put in a very small amount as, once the action is started, it goes on without further catalysis."
Dr. Moore attached a small tube of colorless gas to the side valve on the gas cylinder, and opened the glass stop-cock on it. A hiss of escaping gas under pressure, and the professor removed the emptied tube.
"The gas I have allowed to flow in is a form of gaseous sodium metal. I suppose really I should say a mixture of colloidal sodium vapor and inert argon. The sodium alone will not cause the catalytic action, the argon being necessary to the action. Please note the burning jet under the cabinet."
The flame had suddenly turned from the blue of a carbon monoxide flame to the bright yellow-orange, so well known as the flame-test color of sodium or its compounds.
"Remind me to shut off the gas and remove the plates in four minutes. In the meantime, let us look over this Z-ray machine."
* * *
The professor plugged the electric cord of the big machine into the wall socket and snapped on a switch at the base of the aluminum casing. Instantly a brilliant red streamer flashed toward the ceiling, suffusing the room in a carmine glow. At the base of the machine a blinding bar of crystal light swayed drunkenly for a moment, then steadied to a rigid rod. It struck against a quartz plate and seemed to be disintegrated or absorbed thereby. The two students started back from this demon of light, half frightened by the crackle and roar of the thousands of sparks and streaks of miniature lightning crashing across the gap on the coils below the main part of the machine.
"Have no fear, young men. The light is quite harmless as long as you do not get the crystal light on you. Note -- it is not white; it is simply a rod of cold, crystal-colored light. You are conscious of its extreme intensity. Some of its intensity is converted into radiant energy as it strikes the quartz plate, the only thing I have found that is not affected by the Z-ray. It alone I have found will disintegrate the ray -- how, I do not know."
"My word! What a machine! Tell us what it is and how it works."
Manoras switched off the machine and mopped his forehead with a white handkerchief. The sudden change had rather upset the nerves of the two young men.
"As you may have guessed, this machine is for the purpose of increasing the length of the path of the particles in any liquid or solid body -- a sort of stretching machine. Every particle has its own period of vibration, and to increase the length of the vibratory path one must get into tune with the vibration, so to speak. If one tries to increase the length of the swing of a pendulum, he must move his hand at the same speed and vibration as the pendulum. If we can push the particles in some way in their path so as to increase the length of their paths, we will reach the point where the size and speed of the particles will cause them to become invisible."
"Yes, but how can this infernal red streak and glow cause that change? I don't see any connection between this machine and pushing particles around."
Jerry Murphy spoke rather belligerently, and the professor smiled at the impetuous lad he had had for so many months in his classes.
"Jerry," began the kindly voice, "I realize that there is apparently no connection between the machine and increasing the velocity of molecules. You will get more from the idea if you will suspend judgment a while. The red glow is caused by the colloidal gold in the ruby glass over the top. The particles of the glass are exceedingly small aggregations of molecules of gold suspended in the super-cooled liquid we call glass. These transmit and reflect red light. The size of the colloidal particle controls the color of the light to be reflected or transmitted. In the case of the blue light collected from tobacco smoke or some wood smokes, the particle is of such size as to cause Tyndall's law to take effect. You will remember Tyndall found that in reflecting white light, colloidal particles of this size reflect the colors of the rainbow in intensities inversely proportional to the fourth power of their wavelengths. Thus, since the blue light has the shortest wavelength, the inverse fourth power would be the largest number and hence the greatest color in visible intensity. Lilies owe their white color not to white pigments but to the diffusion of light striking the very tiny colloidal bubbles of air in the lily petals. Of course, when all colored lights striking the lily petal are diffused thoroughly, they mix and form white light. The same phenomenon is found in the case of white hair -- no white pigments are found -- only colloidal bubbles of air to so diffuse the light as to appear white. As to this machine, the red light is purely accidental. I did not design the machine to make red light. I used ruby glass because I find the Roentgen rays do not penetrate the glass as was heretofore believed. The light is a byproduct of the true purposeful action of the machine. Observe, please."
Dr. Moore took off the red cap of glass from the machine, exposing the five anodes arranged in an arc, each pointing toward a central point in the lower body of the aluminum casing. Opposite each anode was a beautifully coiled tungsten wire cathode from which electrons were discharged at the anode. All these anodes were so leveled and arranged that all the angles of incidence in reflecting the bombardment of electrons focused at one narrowing slit -- a sort of rectangular funnel pointing straight downward toward the quartz plate at the bottom where the rod-like ray of cold light was focused.
"When this five-circuit X-ray machine operates, all the reflecting anodes have their positions fixed to throw all X-rays generated to this one point -- the vortex of the funnel-like piece of the casing. That metal looks like aluminum but is really a lead alloy of that metal. It is especially efficient in stopping Roentgen rays. Please observe that I can control each of these five circuits separately."
"Professor! The cabinet!" Manoras cried in alarm.