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taking place, might with the firft Motion compound 
a Curve j but ftill the Rcfiftance of the Air would 
fbon deftroy the original Impulfe, could a few Revo- 
lutions be performed? and befides, one Revolution 
could not be performed, becaufe the fame Stream of 
Air that began the Motion, mull be contrary to it in 
its Rcturm 
A Finger held on the right Hand near the pendu- 
lous Body, when fufpended from a fixed Point, will 
make it revolve from Weft to Eaft ; but then it mull 
be applied and removed alternately : The repulfive 
Force therefore which the Arm may acquire, by being 
held in the Sphere of the Effluvia^ is infufficientj for,, 
as it is in one Place, it muft impel only one way, and 
conftantly the fame way ? and therefore, like a Stream 
of Air in the Room, though it might create the Be- 
ginning, it muft hinder the Completion of a Revo- 
lution. 
Sometimes I have doubted, whether tlic Pulfe of 
the Arm might not be aflifting in giving a projedrile 
Motion. When one Leg is laid over the Knee of the 
other, a Motion and Heaving of the Leg that lies 
over, anfwering to> every Stroke of the Pulfe, is very 
apparent at a Diftance : The Arm therefore in fome 
Poftures, in which its great Artery meets with a pro*- 
portionable PrelTure or Refinance, may have a con*- 
ftant Motion, though le.fs perceivable. 
What feemed the moft probable Solution, was this *. 
When the Arm is extended, tiae Pofture being un- 
eafy, there muft be a Readlion of the Mufcles, or 
a continual palling of the Arm towards the Body. 
When therefore the right Arm isr made ufc of, the 
pulling wili.be from Right to Left<> and confequently 
