“He took off his hat and went over to the border of the patch. He touched—just barely touched the brim of the hat to the gray matter and held it up. Already a growth was moving up the linen. He nodded, then threw it away, onto the sand. Speechless, we watched it fade away under the merciless attack of that horrible stuff, and then, in turn, the gray fungoid growth wither and disappear.
“‘Now do you understand? Do you see vat I meant? Vood, steel, linen—eferyt’ing vat it touches it eats. It grows fast—like flame in dry sticks. All-consuming. Aber—siest du—dot sand—ven it touched dot, it died. It starved. Und see! Look close—more closer still at dot sand. Do you see anything odd about it?’
“I shook my head. It looked very fine and light, but I could not see anything unusual.
“‘No? Iss it not glass, dot sand? Look at it und at der sand vere dot T’ing has not been, and see if it is not so different.’
“I picked up some sand from under my foot. And then I saw what he had seen at once. The sand in my hand was coarser, dirtier—in short, like any fine-grained sand you may have seen. But the sand where the Grey had fallen was clear, glasslike. It was almost transparent, and I saw that what was there was a mass of silicon particles. I nodded.
“‘Yes,’ I said, ‘I see now. That stuff has eaten out every particle of mineral, of dirt and dust, but not the silicon!’
“‘Egsactly! Und dot iss vat has safed us from—Gott only knows vot! I do not know what dot stuff vill eat, but I do know it vill not eat silicon. Vy? I do not know. Dot iss yet a mystery. So—it starts,—ach, dot too, I do not know—but it starts somewhere. Und it eats und grows, und grows and eats, and eferyt’ing vot it touches it consumes—egcept sand. Sand stops it.
“‘It eats out der stuff in der sand, but not der silica, und starves and dies. It is a miracle. If der sand vas not here—ach, Gott!—it vould keep on going until—vell—I do not know! I haf nefer seen dot before. I am intrigued, und I am going to take dot stuff—oh, only a liddle bit—und I shall not rest until I haf learned something about it. Und, because I haf seen it does not lige sand, I vill make for it a cage—a liddle box of glass, und study it lige it vas a bug. Not?’
“We returned to where our natives still stood with our packs. We quickly fitted together some microscopic slides into a rough box and bound it about with string. With it, we returned to the edge of the gray patch. Von Housmann knelt down and carefully scooped up a bit of the fungus with a glass spatula he had brought along. He dumped this into his box and waited. In five minutes it had disappeared. He looked up blankly.
“‘You forget, Sigmund,’ I said, smiling at his woeful expression. ‘It starves on silicon. It won’t live in glass.’