"How is that?"
"It attaches itself almost like a horde of microscopic magnets. It literally burrows into the surface of the metal."
"You don't mean that!"
"I do. Its presence breaks down the surface tension, as we had supposed. The substance actually then works its way into the interstices of the molecules. As the colloid increases in quantity, its molecules loosen the bond between the molecules of the metal, giving them increased freedom of motion.
"This can be aggravated by frictional contacts, and finally we have the molecular interchange that binds the two pieces into one."
"The only metal that would be clean would be that which had been hermetically sealed since before the appearance of the comet," said Ken. "Look—wouldn't this affinity of the dust for metal provide a means of purifying the atmosphere? If we could run the air through large filters of metal wool, the dust would be removed!"
"Yes, I'm very sure we could do it that way. It would merely require that we run the atmosphere of the whole Earth through such a filter. Do you have any idea how that could be done?"
"It would work in the laboratory, but would be wholly impractical on a worldwide scale," Ken admitted. "How will we ever rid the atmosphere of the dust! A colloid will float forever in the air, even after the comet is gone."
"Exactly," Professor Maddox said, "and, as far as we are concerned, the whole atmosphere of the Earth is permanently poisoned. Our problem is to process it in some manner to remove that poison.
"During the past few days we have come to the conclusion that there are only two alternatives: One is to process the whole atmosphere by passing it through some device, such as the filter you have suggested. The second is to put some substance into the air which will counteract and destroy the dust, precipitate it out of the atmosphere."