[ i8i ] 
That in feveral of them the fiefhy fibres 
are not in the fame direction with the ten¬ 
don, that others pafs over joints, and that 
all the mufcles in their adtion oppofe a 
refinance to the bone which ferves them as 
a fupport, and which refinance dedroys 
one half of their whole force. 
Borelli, who has entirely dedicated to 
thefe calculations, has demondrated that 
the abfolute force of a mufcle is the fmall- 
eft portion of all the power it employs to 
produce an effedt. I fhall adduce the del- 
toide, as affording one of the mod: striking 
inftances of this nature. 
“ Let us fuppofe,” fays he, “the weight 
of the arm to be 4 pounds, and from the 
ends of the fingers be fufpended a weight 
of 22 pounds. Let us now examine the 
force by which the deltoide mufcle raifes 
the humerus, fuppofing it to be raifed by 
the adtion of this mufcle alone. Now, if 
the whole length of the arm be divided 
into 
