[ 5 +° 1 
fifty-fourth, one- fourteenth, one-eightieth, one-fixty-' 
feventh, one -fourteenth, one-lixteenth ; the greateft 
errors being where the lpaces were the Ihorteft. In 
other refpedts, the plates feemed to perform their duty, 
in the water, well enough, tho’ the lea was as rough, 
in this voyage, as our fmall vefiel would well bear. 
Lafily, Being, for fome time, on board the Fortune 
Hoop of war, commanded by Alexander Campbell, 
Kfq; in company with Dr. Knight, for the pur- 
pofe of making trial of his new- invented fea-com- 
palfes, I had frequent opportunities of making ufe of 
thefe machines, by comparing them with one an- 
other, with the log, and with real difiances ; and 
having, by repeated trials, pretty well afcertained the 
number of turns of the plate, that was equal to a 
given lpace, by the help of the log, in the manner 
before defcribed, when the fhip was upon a middle 
velocity ; 1 found the lpaces, l'o meafured, nearly con- 
fiftent with themfelves, and with the truth : But all 
this while the wdnds and weather were very mo- 
derate. It afterwards happened, that we run 1 8 
leagues in a brilk gale of wind, w’hich, tho’ not fair 
for us (being before the beam), yet drove us fome- 
times at the rate of 8 knots an hour, as appeared by 
heaving the log. During thus run I obferved, that the 
refiftance of the water, to the line and plate, was very 
confiderable, and increafed the friction of the fpindle 
l'o much, as to prevent it from beginning to turn, till 
the plate had twilled the line to i'uch a degree, that 
when it did fet a going, it would frequently run i yo 
or 200 turns at once. I alfo obferved, that the wind 
coming acrofs the courfe of the fiiip, blew the cord a 
good deal out of the direction of the fpindle, and 
caufed 
