Hcemajlatics. 173 
ing Nature mnft exert a like Power ; not that 
wc are to fuppofe that the growing Fibres are 
forcibly ftretched out at each End, in the man-^ 
ner they were in this Experiment : Nature in 
the extending a growing Fibre rather effefts 
it by the gentle Expanfions of Warmth, which 
exerting its Efficacy on every individual Parc 
of each Fibre, does thereby gradually lengthen 
it. But yet the whole Sum of this Power 
mud be fuperior to the Refiftance of all the 
Fibres which conned this Jundure. 
54. It may not be improper here to fubjoin 
an Account of fome of the like Experiments 
which the ingenious and learned Profeffor Pe- 
ter Van Mujjchenbroek of Utrecht made on 
feveral other animal Subftances, viz. finglc 
Threads of Silk from the ChryfaJis of a 
Silk Worm were torn afunder, fome with 
the Weight of eighty Grains, and others 
“ with intermediate Weights from eighty to 
ninety Grains. IntroduEiio ad coharentiam 
corporum firmorum, p. 520, &c. 
“ 5j. Fifty feven of thofe Threads, when 
but little twifted were as big as a human 
Hair, thefe fuftained 4845 Grains, when 
they break afunder, viz. each eighty five 
Grains. 
j 6 . Affair 
