216 MifceUaneous Ohfematimis; on. ; 
imputes it to the Properties that Salts ha^Q, 
when he fays, the jhooting of any Metal pro¬ 
ceeds generally , merely from Cryfai, combine, 
mg with it in the Concodiiap and Formation of 
the Maps. And again, Metallme .Matter , 
when pure andjimple, never foots into an an - 
' gulated Figure , nor fs indeed capable of doing 
that. c fhe Bodies incorporated with Metals, 
and difpofmg them to fhoot into angulated Fi¬ 
gures , are either Sulphur, (by which he muft 
mean the Sal Acidum of Sulphur) or Cry- 
jlah “ Iron concreting with Cryltal deter- 
mines it to a rhomboidal Figure, Ftn to a 
quadrilateral Pyramid, head to a cubic Form . 
If Cry ft al be pure it (hoots into a fixfided 
pyramidal Figure, or into a Pyramid erebted 
upon a Column, each AiVajix Sides and An¬ 
gles F He moreover fuppofes, (( the Bafis of. 
ail tranfparent Gems to be a cryftal'me Mat¬ 
ter different in Hardnefs, and coloured by 
metallic Mixtures : Lead imparts a yellow* 
Fin a black % Copper a blue or green, 
. Iron a purple, an amethyitine, and various 
Sorts of red. The Figures of all angular 
opake Foffils are owing to the like cryftalioe 
Matter, but in them the metallic Matter. 
{p much exceeds the cryftaline, as to render 
the Body opake 
f And fometimes a yellow, as Several large Grains of Tia 
in tny Pofleffien prove. 
" f See Woodward's Foffils, VoL I. p. i 88 , and 220. 
o That 
