Holding the little round brass case with his left finger and thumb, he gradually with his right hand approached the heathenish idol, sliding the False God slowly along the polished table-top towards the instrument. It came closer and closer. It was at 9 inches, 6 inches, 3 inches, ... but there was as yet no apparent effect, when, suddenly, with the Pot-bellied Dwarf Deity at about 2 inches off, or a little less, the needle behaved like a pointer: it stood immovable, held rigidly by some strange force. The stud, dear friends, but how could Humphrey de Bohun know that?
"There! You see that? See that? See that?" squeaked the Professor triumphantly. "Now I want you to test it for yourself. Move the little devil away! Move it yourself! Humphrey, move it yourself!"
Humphrey de Bohun very slowly pushed back the crystal, and almost immediately the needle trembled again.
"There!" said the Professor in happy confidence, leaning back. "There! What did I tell you?"
"Well, what of it, Bill?" said the harassed master.
"What of it?" answered his cousin. "The Emerald. Ah! the Emerald!" and he rubbed his hands together.
"I don't understand a word you're saying," said poor Humphrey.
The Professor leaned forward and tapped his cousin twice upon the shoulder with that knotted forefinger.
"That instrument," he said, as solemnly as such a voice can say anything, "tells a crystal close at hand. According to the cube of the distance. I have to use it perpetually. Very well known. German, you know—wonderful people, the Germans. It was Meitz's idea," he went on, adding verisimilitude by the effective use of detail. "But he couldn't have done it without Speitzer. Often like that in research work. Any doubt about a crystal's character. Even amorphous—put that thing close enough, and it points at once. Now do you see? Eh! Now do you see?"
"Not exactly," said Humphrey de Bohun.