"How did you get on with your problem?"
"I didn't," he replied. "The truth is, I got side-tracked on something else."
Then, suddenly becoming conscious of his pipe, he thrust it hurriedly into his trousers pocket.
"For heaven's sake go on smoking!" said the girl. "I don't believe you could think at all without your pipe."
"That's true, too," said Bennie, replacing it where it belonged, with gratitude. "Do you mind taking a look at these equations? I'm after something different this time—not as hard as the other one—but I'm not sure of the solution." He laid his note-book down before her.
The girl glanced at it thoughtfully for a moment, and, drawing toward her a pad of yellow paper, she swiftly integrated the equation before Bennie's embarrassed but admiring eyes.
"I suppose one gets groggy occasionally," she said. "Of course I can see that you're on some gravitational problem."
"Yes," he replied; "I'm trying to calculate the rate at which the velocity of the Flying Ring—Pax's antigravity machine that I found up in Labrador, you know—would increase as it left the earth if I took it out into space. The attraction of gravitation, at a distance, say, of twelve thousand miles above the earth would amount to comparatively little, and our velocity would increase at a simply terrific rate. I must get an absolute solution of the problem. Skooting round in space would have to be done by a sort of dead reckoning, I suppose, anyhow, but a knowledge of our velocity would be essential, wouldn't it?"
"By 'our velocity' do you mean that you are planning to take me with you?" inquired the young lady pleasantly.
At this highly indelicate suggestion, Professor Hooker stared at his fair companion blankly.