experimental work on the silent motor. The machine that had been
blown through the roof was useless now, and it was sent to the
scrap heap, after as much of it as possible had been salvaged.
Then Tom got another piece of apparatus out of his store room and
began all over again.

He worked along the same lines as at first--providing a chamber
for the escaping gases of the exhaust to expend their noise and
energy in, at the same time laboring to cut down the concussion
of the explosions in the cylinder without reducing their force
any. And that it was no easy problem to do either of these, Tom
had to admit as he progressed. All previous types of mufflers or
silencers had to be discarded and a new one evolved.

"Jackson, I need some one to help me," said Tom to his chief
mechanician one day. "Haven't you a good man who is used to
experimental work that you can let me take from the works?"

"Why, yes," was the answer. "Let me see. Roberts is busy on the
new bomb you got up, but I could take him off that--"

"No, don't!" interposed Tom. "I want that work to go on. Isn't
there some one else you can let me have?"

"Well, there's a new man who came to me well recommended. I
took him on last week, and he's a wonderful mechanic. Knows a lot
about gas engines. I could let you have him--Bower his name is.
The only thing about it, though, is that I don't like to give you
a man of whom I am not dead certain, when you're working on a new
device."