: E ] 
in every Aggregate of fuch particular faline Par- 
ticles. 
XXVIII. 
Hence it is, that Salt Armoniac fo elegantly imi- 
tates the Branches of a Tree; Salt of Hartjhorn a 
Quiver of Arrows ; Salt of Tin fhoots into Lines like 
little Needles, which fpread themfelves every Way 
from a Point, as from a Centre, fo as to reprefent 
a Star, &c. Now can it be imagined that thefe, or 
any other kind of Salts, would immutably and per- 
petually coalefce into Chryftals of the fame regular 
figure and Shape from any other Principle ? 
XXIX. 
Since therefore we have fo much Reafon to be- 
lieve that Salts of all kinds, and even the Rays of 
Light are endued with a polar Virtue, that is, every 
Corpufcle attrafls on one of its Sides, and repels on 
the other; and fince it is a well known Axiom, that 
Nature is ever frugal in Principles, I think it not 
at all unphilofophical, or contrary to any of the 
known Laws of Nature, to believe that every Parti- 
cle of Matte? in the World is endued with an at- 
tractive and repulftve Property. 
XXX. 
Thus then, if the conftituent Corpufcles of the 
mufcular Fibres are formed together according to 
this Law, if they are all united at particular Points 
cor- 
