[ 31 ] . - 
of fome bodies. Among other things, that occurred 
then to me, I thought it might be ufeful to know 
the fpeciAc gravity of men. In order to make fome 
experiments on this fubjectt, I got a cittern made, of 
78 inches in length, 30 inches wide, and 30 inches 
deep : it was cOnttrudted as near a parallelopiped as 
the workman could, to prevent tedious operations in 
computing the horizontal fedlions of the cittern by 
the furface of the water. I then endeavoured to find 
ten perfons, fuch as I propofed to make the experi- 
ments wkhal ; namely, two of fix feet high, two 
of five feet ten inches, two of five feet eight inches, 
two of five feet fix inches, and two of five feet four 
inches. One of each height I propofed fhould be a 
fat man, and the other a lean one; but I could not 
fucceed in procuring fuch men ; and, after waiting 
till near the middle of Odtober, I was obliged to put 
up with fuch, as would fubmit themfelves to the ex- 
periment at that feafon of the year. They were all 
labouring men, belonging to the ordinary of Portf- 
mouth yard, and, except one or two of them, who 
were middling fized men, were for the moft part 
very thin and ilim made perfons. I had alfo pro- 
vided a Aiding meafure to take their heights, and 
fcales to weigh them in. Every thing being pre- 
pared, each man ttript himfelf in an adjoining room, 
and put on a pair of trowfers for decency’s fake : his 
height was firft taken, then his weight, and then he 
immerfed (fortiAed with a large dram of brandy). 
A ruler, graduated to inches, and decimal parts of an 
inch, was Axed to one end of the cittern, and the 
height of the water noted before a man went in, 
and to what height it rofe when he ducked himfelf 
under 
