ow engaged in
labeling them with letters. But instead of employing the usual
geometrical symbols A, B, C, and so on, he was skipping about through
the alphabet, and Irving immediately perceived that he was not choosing
letters at random. Irving observed that the initials of his own name, I,
C, U, formed, as it were, the corner-stone of the geometrical edifice.

At that moment Westby coughed--an unnatural cough. And instantly a
miracle happened; every single wooden eraser--there were half a dozen of
them--leaped from its place on the shelf beneath the blackboard and
tumbled clattering down the steps to the floor. At the same instant
Westby flung up both arms, tottered on the topmost step, and succeeded
in regaining his poise with apparently great difficulty.

The class giggled.

"Mr. Upton, sir! Mr. Upton, sir!" cried Westby excitedly. "Did you feel
the earthquake? It was very noticeable on this side of the room. Do you
think it's safe for us to stay indoors, sir? There may be another
shock!"

"Westby," Irving's voice had a nervous thrill that for the moment
quieted the laughter, "did you cause those erasers to be pulled down?"

"Did I cause them to be pulled down? I don't understand, sir. How could
I, sir? Six of them all at once!"

"Bring me one of those erasers, please."

Westby stooped; there was a sound of snapping string. Then he came
forward and presented the eraser.

"You tied string to all these erasers, did you?" Irving examined the
fragment that still clung to the object. "And then arranged to have them
pulled down?"

"You see how short that string is, sir; nobody could have reached it to
pull it. Didn't you feel the earthquake, sir? Didn't you see how it
almost threw me off my feet? Really, I don't believe it's quite safe to
stay here--"

"You may be right; I shouldn't wonder at all if there was a second shock
coming to you soon," said Irving, and the subdued chuckle that went
round the class told him he had scored. "You may now demonstrate to the
class the Theorem assigned you."

"Yes, sir." Westby turned and took up the pointer.

"We have here," he began, "the two triangles I C U and J A Y--with the
angle I C U of the one equal to the angle J A Y of the other." The class
tittered; Westby went on glibly, bending the lath-like pointer between
his hands: "Let us now erect the angle K I D, equal to the angle I C U;
then the angle K I D will also be equal to the angle J A Y--things equal
to the s