( *39 ) 
the Leaver begins to move. This will be evident, if? 
you let the Weight 4 hang at D, whilft the Weight 1 
ies above it : For if then you move the Leaver, the. 
Weight 1 will rife four times as fall as the Weight 4. 
XI. A Method for rowing Men of War in a 
Calm . Communicated by Monfieur Du Quet. 
T O perfect the Art of Navigation; Two Things 
feem principally wanting ; viz,. An eafy Me- 
thod for finding the Longitude at Sea ; and a Way to 
give a Veffel its Gourfe, when, there’s no Wind flir- 
ring. 
I flatter my felf to have found the laft ; and hope 
to make it appear, by Reafon and Experiment, That, 
a Man of War may make a League an Hour in a 
Calm, by Means of revolving Oars, which are eafily 
apply ’d to the Sides of the Ship, without occafioning . 
any Incumbrance : As I fhall make appear by the fol- 
lowing Account, after having deliver’d my Notion of 
the Motion of Bodies in Fluids* . 
x f * 
A Body fwims upon Water, when it weighs lefs 
than the Volume of Water, whofe Place it takes up; 
and it finks more or lefs in the Water, only in propor- 
tion as its Volume is more or lefs increas’d. 
A Body lying in Rill Water, is as it were in jEquili- 
Irio ; the leaR Effort gives it Motion, and makes it 
lofe that ^Equilibrium. If the Effort be continued, thoV 
ever fo little, the Motion it communicates will be ve- 
ry. 
