(n) 
plain fome Terms, which in nominating 
the parts of Chryftal I do employ. 
Chrjfid is compofed of two Hexago¬ 
nal Pyramids, and an intermediate Co- 
lumn like\yife hexagonal: VVhere I call 
thofe the Extreme Solid Angles^ tha^ 
make up the Tops of the Pyramids 5 but 
thofe the Intermediate [olid Angles■^which. 
are made in uniting the Pyramids with 
the Columne. After the like manner I 
call the Planes of Pyramids , Extreme 
planes, and the Planes of the Columne, 
Intermediate planes. The Plane of the 
Bafts is a Sedlion perpendicular to. all the 
Intermediate planes. The Plane of the 
Axis is a Sedion, wherein is the Axe of 
the Chryftal, which is com poled of the 
K^xes of the Pyramids, and the Axe of 
the Columne. 
The place, where the firft concretion 
of a Chryftal begins, is doubtful whe¬ 
ther it be between two Fluids., or between, 
a Fluid and a Solid, oc in a Fluid ft felft 
But the place, whence a Chryftal alrca”, 
dy formed increafeth, is folid on that 
part where the Chryftal leans on it, 
v/hether it be a Stone, or fome ocher, 
ChryAal bcfore formed v and on the o- 
' ' '. E ' thcE. 
