[ 45 8 ] 
An Icicle broken from a Grotto (I fuppofe 
Stalactites) HT.Slare, in Harris. . i.ipo 
Chalk, as round by Dr. blare. Harris. 1.079 
The mean gravity of Stone appears to be to that 
of water as about two and a half to one, and many 
Tones of great hardnefs, fuch as the Onyx, Tur- 
quoife, Agat, Marble, Flint &c. do not much ex- 
ceed that weight. It may therefore well be doubted 
whether fuch Stones whofe fpecific gravity comes 
up to near three times that of water, or even beyond 
it, owe their den fit y to metalline additions; or whe- 
ther they are really formed of a different Ipecics of 
matter, as the Diamond feems to be. 
Coral by its denfity appears to be a ftone, tho in 
a vegetating ftate: or it may pofllbly from fome 
late obfervations, be of an animal nature. 
What is called Lapis Hibernicus, is a foft Tone 
containing Vitriol. 
We have not many obfervations upon Earths : 
by thofe we have, it feems probable that they con- 
tain the fame kind of matter in a lax form, of 
which Stones are a more folid and denfer con- 
cretion. 
Lapis de Goa is but a trifling compofition, per- 
naps hardly worth retaining in the tables. 
What fpccies of body fliould Alabafter be ac- 
counted? which with a ftone-like hardnefs, yet falls 
10 much below other Stones, or even Earths, in 
gravity. 
TABLE 
