54 
Figures of Gem-Salt, 
PLATE I. - N° L 
Figures c/'Sal-Gemm^j or Rock-Salt, 
a - A fquare pyramidal Hollow Body, fome- 
what opake, whofe four Sides are 
Hoping Triangles, and meet in a Point 
at Top. 
b - A body with four equal Hoping Sides, 
terminated by a Plane at about half the 
Height of the former : not much trans¬ 
parent, but hollow. 
c - A Body rifing about the Height of the 
laft, in the Manner here fliewn, and 
very transparent except as the Lines 
imply. 
d - A fquare thin Plate, exceedingly trans¬ 
parent. 
e - An hollow Pyramid, whofe Bafe is a 
Redlangle, and whofe Sides are Hop¬ 
ing and terminate in a Point; the 
whole femi-transparent. 
f~ A narrower hollow ReCtangle, with 
Hoping Sides not much transparent, 
riling about half as high as the pre¬ 
ceding, and then ending in a flat Sur¬ 
face that is very transparent. 
g - Another hollow Figure, having a rect¬ 
angular Bafe, very tranfparent, with 
Hoping Sides as in the Picture. 
h - An 
