THE 
INTRODUCTION. 
I. A S an animal Body confids not only 
JLX of a wonderful texture of folid 
Parts^ but alfo of a large proportion of 
Fluids, which are continually circulating 
and flowing, thro* an inimitable Embroidery 
of Blood- VeflTels, and other inconceivably 
minute Canals : And as the healthy State 
of an Animal principally confifts, in the 
maintaining of a due Equilibrium between 
thofe Solids and Fluids ; it has, ever fince 
the important Difeovery of the Circulation 
of the Blood, been looked upon as a Mat- 
ter well worth the enquiring into, to find 
the Force and Velocity with which thefe 
Fluids are impelled; as a likely means to 
give a confidcrablc Infighc into the animal 
OEconomy. 
2. Several ingenious Perfons have from 
time to time, attempted to make Eftimates 
of the Force of the Blood in the Heart and 
Arteries, who have as widely differed from 
each other as they have from the Truth, 
for want of a fujfficient Number of Data to 
argue from : Had Perfons of their Abilities 
been 
