"And here is another fact any schoolboy will know. If a sheet of glass is smashed, Kemp, and beaten into a powder, it becomes much more visible while it is in the air; it becomes at last an opaque, white powder. This is because the powdering multiplies the surfaces of the glass at which refraction and reflection occur. In the sheet of glass there are only two surfaces, in the powder the light is reflected or refracted by each grain it passes through, and very little gets right through the powder. But if the white, powdered glass is put into water it forthwith vanishes. The powdered glass and water have much the same refractive index, that is, the light undergoes very little refraction or reflection in passing from one to the other.
"You make the glass invisible by putting it into a liquid of nearly the same refractive index, a transparent thing becomes invisible if it is put in any medium of almost the same refractive index. And if you will consider only a second, you will see also that the powder of glass might be made to vanish in air, if its refractive index could be made the same as that of air. For then there would be no refraction or reflection as the light passed from glass to air."
"Yes, yes," said Kemp. "But a man's not powdered glass!"
"No," said Griffin. "
"Nonsense!"
"That's from a doctor! How one forgets! Have you already forgotten your physics in ten years? Just think of all the things that are transparent and seem not to be so! Paper, for instance, is made up of transparent fibres, and it is white and opaque only for the same reason that a powder of glass is white and opaque. Oil white paper, fill up the interstices between the particles with oil, so that there is no longer refraction or reflection except at the surfaces, and it becomes as transparent as glass. And not only paper, but cotton fibre, linen fibre, wool fibre, woody fibre, and
"Of course, of course!" cried Kemp. "I was thinking only last night of the sea larv? and jelly-fish!"
"
"Yes?"
"You know the red colouring matter of blood—it can be made white—colourless—and remain with all the functions it has now!"
Kemp gave a cry of incredulous amazement.
The Invisible Man rose and began pacing the little study. "You may well exclaim.[6] I remember that night. It was late at night—in the daytime one was bothered with the gaping, silly students—and I worked there sometimes till dawn. It came suddenly, splendid and complete, into my mind. I was alone, the laboratory was still, with the tall lights burning brightly and silently… 'One could make an animal—a tissue—transparent! One could make it invisible! All except the pigments. I could be Invisible,' I said, suddenly realising what it meant to be an albino with such knowledge. It was overwhelming. I left the filtering I was doing, and went and stared out of the great window at the stars. 'I could be Invisible,' I repeated.
"To do such a thing would be to transcend magic. And I beheld, unclouded by doubt, a magnificent vision of all that Invisibility might mean to a man. The mystery, the power, the freedom. Drawbacks I saw none. You have only to think! And I, a shabby, poverty-struck, hemmed-in[7] demonstrator, teaching fools in a provincial college, might suddenly become—this, I ask you, Kemp, if
"And after three years of secrecy and trouble, I found that to complete it was impossible—impossible."
"How?" asked Kemp.