ood of a particle of matter,
there is a pucker or a wrinkle in space. My father has found that by
suddenly removing a portion of matter from out of space, the pucker
flattens out. If the matter is heavy enough and its removal sudden
enough, there is a violent disturbance of space. By planning all the
steps carefully my father has succeeded in swinging a section of
space on a pivot through an angle of 180 degrees, and causing two
portions of space to change places through hyperspace, or as you might
express it popularly, through the fourth dimension."

* * * * *

Phil held his hands to his head.

"It is not difficult," she went on smiling. "Loan me your pocket knife
and a piece of paper from your notebook. If I cut out a rectangular
piece of paper from this sheet and mount it on a pivot or shaft at A
B, I can rotate it through 180 degrees, just like a child's
teeter-totter, so that X will be where Y originally was. That is in
two dimensions. Now, simply add one dimension all the way round and
you will have what daddy is doing with space. He does it by shoving
fifty or a hundred pounds of lead right out of space; the sudden
flattening out of the tensors causes a section of space to flop
around, and two portions of space change places. The first time he
tried it, his desk disappeared, and we've never seen it again. We've
thought it was somewhere out in hyperspace; but this terrible story of
yours about disappearing safes, and the fact that you have this
picture, means that someone has got the desk."

"Surely you must have suspected that long ago, when the disappearances
first began?" Phil suggested.

"I've just returned from Europe," said Miss Bloomsbury. "I was
tremendously puzzled when I got my first newspapers in New York and
read about the safes. Gradually I gathered all the news on the
subject, and it seemed most reasonable to suspect this gangster
engineer."

"Great minds and same channels," Phil smiled. "But your father. Why
didn't he speak up when the safes began to pop?"

"Ha! ha!" she laughed a tinkly little laugh. "My father doesn't know
what safes are for, nor who is President, nor that there has been a
war. Mother and I take care of him, and he works on tensors. He has
probably never heard about the safes."

* * * * *

"What were you going to do around here?" Phil asked, marveling at the
courage of the girl who had come to look the situa