stop
cocks.

It would be interesting to know the kind of man this precocious boy
inventor became, or whether he received suitable reward for his
important improvement. We search in vain; no mention of him is to be
found. Let us, however, do our best to repair the neglect and record
that, in the history of the steam engine, Humphrey Potter must ever be
honorably associated with famous men as the only famous boy inventor.

In the development of the steam engine, we have one purely accidental
discovery. In the early Newcomen engines, the head of the piston was
covered by a sheet of water to fill the spaces between the circular
contour of the movable piston and the internal surface of the cylinder,
for there were no cylinder-boring tools in those days, and surfaces of
cylinders were most irregular. To the surprise of the engineer, the
engine began one day working at greatly increased speed, when it was
found that the piston-head had been pierced by accident and that the
cold water had passed in small drops into the cylinder and had condensed
the steam, thus rapidly making a more perfect vacuum. From this
accidental discovery came the improved plan of injecting a shower of
cold water through the cylinder, the strokes of the engine being thus
greatly increased.

The year 1783 was one of Watt's most fruitful years of the dozen which
may be said to have teemed with his inventions. His celebrated discovery
of the composition of water was published in this year. The attempts
made to deprive him of the honor of making this discovery ended in
complete failure. Sir Humphrey Davy, Henry, Arago, Liebig, and many
others of the highest authority acknowledged and established Watt's
claims.

The true greatness of the modest Watt was never more finely revealed
than in his correspondence and papers published during the controversy.
Watt wrote Dr. Black, April 21st, that he had handed his paper to Dr.
Priestley to be read at the Royal Society. It contained the new idea of
water, hitherto considered an element and now discovered to be a
compound. Thus was announced one of the most wonderful discoveries found
in the history of science. It was justly termed the beginning of a new
era, the dawn of a new day in physical chemistry, indeed the real
foundation for the new system of chemistry, and, according to Dr.
Young, "a discovery perhaps of greater importance than any single fact
which human ingenuity has ascertained either before or since