and thus irregular power. In figure 6, the counterweighted wheel,
revolving twice for each revolution of the crank (A), would allow the
counterweight to descend while the crank passed the dead-center position
and would be raised while the crank had maximum leverage. No mention of
a flywheel was made in this patent.[10]

[Footnote 10: British Patent 1263, August 23, 1780.]

[Illustration: Figure 6.--One of the steam engine "Crank Patents" that
hindered James Watt's progress. This patent, granted to James Pickard in
1780, claimed only the arrangement of counterweights, not the crank. The
crank pin to which the connecting rod was attached is at _Aa_. From
British Patent 1263, August 23, 1780.]

Wasbrough, finding that his "rotchets and clicks" did not serve,
actually used, in 1780, a crank with a flywheel. Watt was aware of this,
but he remained unconvinced of the superiority of the crank over other
devices and did not immediately appreciate the regulating ability of a
flywheel.[11] In April 1781 Watt wrote to Boulton, who was then out of
town: "I know from experiment that the other contrivance, which you saw
me try, performs at least as well, and has in fact many advantages over
the crank."[12] The "other contrivance" probably was his swash wheel
which he built and which appeared on his next important patent
specification (fig. 7a). Also in this patent were four other devices,
one of which was easily recognizable as a crank, and two of which were
eccentrics (fig. 7a, b). The fourth device was the well-known
sun-and-planet gearing (fig. 7e).[13] In spite of the similarity of the
simple crank to the several variations devised by Watt, this patent drew
no fire from Wasbrough or Pickard, perhaps because no reasonable person
would contend that the crank itself was a patentable feature, or perhaps
because the similarity was not at that time so obvious. However, Watt
steered clear of directly discernible application of cranks because he
preferred to avoid a suit that might overthrow his or other patents. For
example, if the Wasbrough and Pickard patents had been voided, they
would have become public property; and Watt feared that they might
"get into the hands of men more ingenious," who would give Boulton and
Watt more competition than Wasbrough and Pickard.[14]

[Footnote 11: Dickinson and Jenkins, _op. cit._ (footnote 5), pp. 150,
154.]

[Footnote 12: _Ibid._, p. 154.]

[Footnote 13: William Murdock, at this time a Bo