de again and sent to him. Besides, he and the boy had to live, and
living is dear nowadays, even in a cottage in an out-of-the-way corner
of Connecticut; and he needed fire and light in abundance for his work,
besides something to eat and decent clothes to wear and somebody to cook
the dinner; and when he took out his diary note-book and examined the
figures on the page near the end, headed "Cash Account, November," he
made out that he had three hundred and eighteen dollars and twelve
cents to his credit, and nothing to come after that, and he knew that
the men who had believed in him had invested, amongst them, ten thousand
dollars in shares, and had paid him the money in cash in the course of
the past three years, but would invest no more; and it was all gone.

One thousand more, clear of living expenses, would do it. He was
positively sure that it would be enough, and he and the boy could live
on his little cash balance, by great economy, for four months, at the
end of which time the Air-Motor would be perfected. But without the
thousand the end of the four months would be the end of everything that
was worth while in life. After that he would have to go back to teaching
in order to live, and the invention would be lost, for the work needed
all his time and thought.

He was a mathematician, and a very good one, besides being otherwise a
man of cultivated mind and wide reading. Unfortunately for himself, or
the contrary, if the invention ever succeeded, he had given himself up
to higher mathematics when a young man, instead of turning his talent to
account in an architect's office, a shipbuilding yard, or a locomotive
shop. He could find the strain at any part of an iron frame building by
the differential and integral calculus to the millionth of an ounce, but
the everyday technical routine work with volumes of ready-made tables
was unfamiliar and uncongenial to him; he would rather have calculated
the tables themselves. The true science of mathematics is the most
imaginative and creative of all sciences, but the mere application of
mathematics to figures for the construction of engines, ships, or
buildings is the dullest sort of drudgery.

Rather than that, he had chosen to teach what he knew and to dream of
great problems at his leisure when teaching was over for the day or for
the term. He had taught in a small college, and had known the rare
delight of having one or two pupils who were really interested. It had