( viii ) 



' hairs is more than 200,000 times hirger than thofc very fmall blood 

 ' vellels in a flv/ 



The author fometimes computes tlie fize of fmall objccls by ali- 

 quot or equal parts of an inch, and, for the more readily placing 

 thefe before the reader's view, the tranflator has fubjoined a fcale of 

 inches divided into feveral different numbers of equal parts, and in 

 each of thefe divifions is marked the proportionate fize of the fame 

 number of i>arts in a fquare inch. 



Further, at H I K L, is given a reprefentation of a cube, and at 

 M N O P, a drawing of a cylinder, in order to convey an idea of 

 thofe figures to fuch readers as have not been much converfant in 

 the doctrine of lolids. The number of parts or circles contained in 

 the cylinder, will not be found to anfwer fo exa6tly to tiie aritli- 

 inetical computation as thofe in the cube, and this is occafioned by 

 the interllices or fpaces between the circles in the cylinder, whicli 

 only touch each other in a point. 





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