[ 6 ] 
gyration) being wanting to perfect the Theory of the 
conftrudtion, I fhall drop the inquiry when I have 
made only one remark more. It is this. The fhort- 
nefs of the Brachia diminifhes the refiftance of the 
Engine to motion ; and, therefore, the inequality 
which I propofed in them was in part to avail myfelf 
of that obvious advantage, without incurring the in- 
convenience of enlarging the pump-bores. I fay 
it is an obvious advantage ; for, the matter in the 
Brachia, that the Equilibrium may be preferved, be- 
ing inverfely as their lengths, and the refiftance to 
motion in the diredt ratio of the fquares of thofe 
lengths, the reftftance of the longer arm is to that 
of the Ihorter as the lengths of them diredtly. 
Queen -fquare, Weftminfter, 
June 22, 1756. 
II. Objerua - 
