It has
to be initiated, laboured over, and pursued in the face of
disappointments, difficulties, and discouragements.
Sometimes the idea is born in one generation, followed out in the
next, and perhaps perfected in the third. In an age of progress,
one invention merely paves the way for another. What was the
wonder of yesterday, becomes the common and unnoticed thing of
to-day.
The first idea of the screw was thrown out by James Watt more
than a century ago. Matthew Boulton, of Birmingham, had proposed
to move canal boats by means of the steam-engine; and Dr. Small,
his friend, was in communication with James Watt, then residing
at Glasgow, on the subject. In a letter from Watt to Small,
dated the 30th September, 1770, the former, after speaking of the
condenser, and saying that it cannot be dispensed with, proceeds:
"Have you ever considered a spiral oar for that purpose
[propulsion of canal boats], or are you for two wheels?" Watt
added a pen-and-ink drawing of his spiral oar, greatly resembling
the form of screw afterwards patented. Nothing, however, was
actually done, and the idea slept.
It was revived again in 1785, by Joseph Bramah, a wonderful
projector and inventor.[5] He took out a patent, which included
a rotatory steam-engine, and a mode of propelling vessels by
means either of a paddle-wheel or a "screw propeller." This
propeller was "similar to the fly of a smoke-jack"; but there is
no account of Bramah having practically tried this method of
propulsion.
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