“Go to it, buddy.”
Roger, with the hand of the youth clutching the coin, got a good snap just as the flash startled and almost stampeded the kangaroo and several horses and a few mules quartered there.
He returned by taxi as the East streaked rosily to the rising of the sun.
“There was the kangaroo, but she had not been out—at least, the attendant vowed she hadn’t,” he said. “But I’ve got her picture to compare with the ghost-one.”
“Clever head,” commended his older cousin. He went away, pleased, to develop, print and fix his prize.
While negative and contact print were being fixed and washed, he sat at the table in the adjoining room where the mysterious voice and roaring cry had been located, thinking hard.
“I wonder,” he mused, “if it could be that the film I used had some sort of emulsion that would be sensitive to rays we don’t see. You can take a picture through a quartz lens in a room that seems to be pitchy black. I’ve done it, with our special equipment. Maybe a film coating that has some light-sensitive ingredient sensitive to high-frequency vibrations of light, could catch what we don’t see, and—who can dispute this?—there may be in the air, all around us, forms of things that we can’t see.”
Science, he reflected, had managed to develop instruments so delicately adjusted that they caught earth tremors and recorded them, when the disturbance might be hundreds, thousands of miles away from the seismograph.
Their own Mr. Ellison, the cleverest and best informed man in the city, on electrical matters, was preparing a camera that ran its film at high speed past an aperture: a light more actinic than sunshine alternately lit and was out, but so rapidly that its flashes impressed pictures lit by it on the film, as many as a half million or more a minute, he believed. The papers had written it up as that many.
And scientific instruments pictured, in graphs, of course, such invisible things as electrical waves; yes, and radio made audible the inaudible electrical frequencies sent by an aerial, caught by another, transformed into sounds by other invisible agencies.