43 2 
Dr. Pearson's Observations 
nearly as should be expected, with their composition found by 
analysis ; and agree sufficiently with the synthetic experi- 
ments, §3. and §6. p.422. 
I did not find that the specific gravity of the same metal, 
under known circumstances alike, was so nearly the same in 
all cases as is stated by most writers. In the preceding expe- 
riments, different parts of the same ingot varied more than is 
commonly supposed in point of specific gravity. 
The specific gravities of the ancient metals, after melting, 
varied between 8,5 and 8,8, or nearly so, § 3 ; and the specific 
gravities of the allays of three to twenty parts of copper with 
one of tin varied between about 8,5 and 8,9, § 6. p. 422. These 
great specific gravities seem surprising, because that of tin is 
only about 7,2, and of copper ingot about 8,420, § 6. p. 422. 
But of all metallic combinations that of copper with tin produces 
perhaps the greatest increase of density. Aristotle made 
this observation long ago,* and the fact is familiarly known to 
manufacturers of bell-metal. But it does not appear that the 
increase of specific gravity is so great as it is stated by Glauber. 
According to him, if two halls of copper and two balls of tin 
of the same dimensions be melted together, the compound will 
afford scarcely three balls of the same dimensions as each of 
the four balls ; and yet the three balls will weigh as much as 
the four balls. — *“ Funde praedictos globulos in unum 
“ iterum effunde mixturam liquefactam in typum globulorum 
* T xvra ya/> S^/t xui woie~ uavov to* oyxo*. (frcti V Sarsfo* jj.biot vaSri tixc», r, 
vlpofyoc, to ae irafj’irav vgepct, m bcev wAuo* to jjyyjiit tl tat cvrzg <TVjj.Qa.Uiy W£§i to* 
xsctKte^o* y.ai to ycifoicv. - • ■ ■■ ■ O' yceg jcarliTsgo; u; iraSof T» ar, atev tS 
tryzSbv y.m aomort, //.ow.— ARISTOTLE, IIEP1 FENE2EHT 
K.AI <J>©0PA2 TO A. Ke<p, ». "Or* eft 
