ory," but that in fact the crank is impractical
because of the irregular rate of going of the engine and its variable
length of stroke. He said that on the first variation of length of
stroke the machine would be "either broken to pieces, or turned
back."[6] John Smeaton, in the front rank of English steam engineers of
his time, was asked in 1781 by His Majesty's Victualling-Office for his
opinion as to whether a steam-powered grain mill ought to be driven by a
crank or by a waterwheel supplied by a pump. Smeaton's conclusion was
that the crank was quite unsuited to a machine in which regularity of
operation was a factor. "I apprehend," he wrote, "that no motion
communicated from the reciprocating beam of a fire engine can ever act
perfectly equal and steady in producing a circular motion, like the
regular efflux of water in turning a waterwheel." He recommended,
incidentally, that a Boulton and Watt steam engine be used to pump water
to supply the waterwheel.[7] Smeaton had thought of a flywheel, but he
reasoned that a flywheel large enough to smooth out the halting, jerky
operation of the steam engines that he had observed would be more of an
encumbrance than a pump, reservoir, and waterwheel.[8]

[Footnote 6: John Farey, _A Treatise on the Steam Engine_, London, 1827,
pp. 408-409.]

[Footnote 7: _Reports of the Late John Smeaton, F.R.S._, London, 1812,
vol. 2, pp. 378-380.]

[Footnote 8: Farey, _op. cit._ (footnote 6), p. 409.]

The simplicity of the eventual solution of the problem was not clear to
Watt at this time. He was not, as tradition has it, blocked merely by
the existence of a patent for a simple crank and thus forced to invent
some other device as a substitute.

Matthew Wasbrough, of Bristol, the engineer commonly credited with the
crank patent, made no mention of a crank in his patent specification,
but rather intended to make use of "racks with teeth," or "one or more
pullies, wheels, segments of wheels, to which are fastened rotchets and
clicks or palls...." He did, however, propose to "add a fly or flys, in
order to render the motion more regular and uniform." Unfortunately for
us, he submitted no drawings with his patent specification.[9]

[Footnote 9: British Patent 1213, March 10, 1779.]

James Pickard, of Birmingham, like Boulton, a buttonmaker, in 1780
patented a counterweighted crank device (fig. 6) that was expected to
remove the objection to a crank, which operated with changing leverage