i.|o Mr. edgeworth’s Experiments upon 
Purfuing the fame reafoning that led me to the lad: experi- 
ment, it occurred to me, that even againft figures of exaCtly 
the fame lhape, the refidance of the air, when the dimenfions 
of the figures were enlarged, would not be increafed in the 
fame proportion as the frze of the planes, but in a much higher 
ratio ; and that, by bending the planes as a fail, the refinance 
would be dill farther increafed, though the feCtion of air, that 
would be intercepted by the planes, mud: by thefe means be 
confiderably ledened. 
The refult far furpaded my expectations. A fquare of tin* 
containing fixteen fquare inches, placed perpendicularly, was 
redded as two and a half. A fquare, containing fixty-four 
inches, or four times the former quantity, indead of meeting 
with a refidance as ten or four times the former refidance, 
required no lefs than fourteen pounds to give it the fame 
velocity. 
Four-tenths (or nearly half as much again) was an increafe 
of refidance that made me fnfpeCt fome error in the experiment ; 
but having repeated it feveral times with great care, and having 
examined all the parts of the machine, I was Fatisfaed that I 
had made no midake. 
1 now placed the parallelogram of nine inches long upon 
the arms of the machine, with its fhorted fides parallel to the 
horizon, bending it to fuch an arch that its chord mealured 
eight inches, and inclining it to an angle of forty-five degrees.. 
And though the feCtioii of air that it intercepted was by thefe 
means diminifhed one-ninth, yet the refidance was increafed 
from five to five and a half. And when the parallelogram 
was bent yet farther, and its chord contracted almod to feven 
inches, the refidance was increafed to five and three-quarters. 
I mention thefe numbers in grofs to avoid confufion ; but in 
the 
