ur model and drawings,
when the boy brought the note. He was a regular messenger boy, I
could tell that. And the note only asked for the model--not for any
of the finished machines, of which I had two. He didn't even want the
drawings, or I might have been suspicious."

"They won't need the drawings as long as they have the model. They
can make drawings themselves," spoke Russ.

"But if they only have the model, and you still have some of the
finished appliances," asked Alice, "can't you get ahead of them
yet?"

"I'm afraid not," Russ replied. "You see, the patent office doesn't
require models to be filed in all cases now. You can get a patent
merely on drawings. They can still get ahead of me."

"Not if you file your drawings now!" exclaimed Ruth.

"Yes, but I'm not ready. You see the machine isn't perfected yet. I
am still working on it. But they can file a prior claim, and get a
patent on something so near like mine that I would be refused a
patent when I applied.

"You see I haven't made any formal application yet. Of course, if it
came to a question of a lawsuit, I might beat them out. But I have no
money to hire lawyers, and they have. The only thing for me to do is
to get that model back before they have a chance to use it to make
drawings from. And how to do it I don't know."

"Do you know who that messenger boy was?" asked Alice suddenly of the
machinist.

"I never saw him before, Miss--no. He came in a taxicab."

"A taxicab!" cried Russ, excitedly. "You didn't say that before. Did
you happen to notice the number?"

If ever Russ Dalwood was thankful it was then, and the cause of it
was that Mr. Burton had a mathematical mind in which figures seemed
to sprout by second nature.

"I did notice the number," he said. "It isn't often that taxicabs
stop out in front here, and I looked from my window as one drew up at
the curb. I was working on your patent at the time. I saw the number
of the cab, later, as the messenger boy rode off in it with the
model."

"What was it?" asked Russ, preparing to make a note.

The machinist gave it to him.

"Now if we can only trace it!" exclaimed the young inventor.

"I guess I can help you out, friend," broke in their own taxicab
chauffeur. "I've got a list of all the cabs in New York, and the
companies that run them." Rapidly he consulted a notebook, and soon
had the desired information. The office of the company was not far
away, and Russ and the girls were soo