MARITIME OBSERVATIONS. 297 
vide them once more, and, continuing the fame obliquity, 
T placed the twenty-four behind each other in a line, 
when the force of the wind being the fame, and the fur- 
face of vane the fame, they moved round with much ’great- 
er rapidity, and perfeQly anfwered my purpofe. 
The fecond experiment that I propofe, is, to take two 
playing cards of the fame dimenfions, and cut one of them 
tran{verfely into eight equal pieces; then with a needle 
{tring them upon two threads one near each end, and place 
them fo upon the threads that, when hung up, they may 
be one exactly over the other, at a diftance equal to their 
breadth, each in a horizontal pofition; and let a {mall 
weight, fuch as a bird-fhot, be hung under them, to make 
them fall in a ftraight line when let loofe. Sufpend alfo 
the whole card by threads from its four corners, and hang 
to it an equal weight, fo as to draw it downwards when. 
let fall, its whole breadth prefling againft the air. Let 
thofe two bodies be attached, one of them to one end of 
a thread a yard long, the other to the other end. Extend 
a twine under the ceiling of a room, and put through it 
at thirty inches diftance two pins bent in the form of fith- 
hooks. On thefe two hooks hang the two bodies, the 
thread that connects them extending parallel to the twine, 
which thread being cut, they muft begin to fall at the fame 
inftant.. If they take equal time in falling to the floor, it 
is a proof that the refiftance of the air is in both cafes 
equal. If the whole card requires a longer time, it {hows 
that the fum of the refiftances to the pieces of the cut card 
is not equal to the refiftance of the whole one™. 
This principle fo far confirmed, | would proceed to make 
a larger experiment, with a fhallop, which I would rig in 
this manner, 
, . ABis 
* The motion of the veffel made it inconvenient to try this fimple experiment, at fea, 
when the propofal of it was written. But it has been tried fince we came on fhore, and 
fucceeded as the other. 
