[ 269 ] 
in Girt at the largeft End, and more than (even high; 
from which Size there are ot’ all Degrees, down to 
the Bignefs of a fmall Pin. As the Size of this 1 aft- 
mentioned is very unufual, I have given a Drawing 
of it, Fig. 1 6. Tab. V. 
The largeft proceed out of a large Courfe or Load of 
Spar; but the (mailed of all from fmall Bits or Lumps 
of Spar ; and the fmall pyramidal apices are generally 
ftuck on upon the Side of the large ones, fometimes 
in diftant Spangles, other times in thin and broken' 
Incruftations. Now the Caufe of thefe different Sizes 
feems to be this : Whcre-ever great Mafies of the fparry 
juice have happened at the fame time to be in a State 
of Fluidity, the exuberant Water drained off fud- 
denly, and confequently left Cavity fufficient for the 
Salts to extend themfelves, there the great Quantities 
of nitrous Salts mixed with the lapideous Juice in- 
cline it to fhoot vigoroufly, and form large Cryftalliza-' 
tions ; and from proportionally lefier Mafies, whilft 
they are indurating, proceed lefler Diamonds. If the 
whole Mafs be impregnated with nitrous Salts, the' 
whole Surface of the Rock {hall rife into Points or 
Spires (21), according as the Mafs is more free or 
more ftubborn to comply with the Agitation. If the 
nitrous Salts are not intimately mixed, but fwim in 
Clouds and Bunches, thofc Lumps only, where the 
Nitre is, fhall be fhot, and the reft be plain. This is 
the Cafe when the fparry Juice gets into its proper 
Nidus , or refts in its Fiflure. But where fmall fcat- 
tcr’d Quantities of this ftony Jutce circulate in the 
fubter- 
(21) See Fig. 4. and Fig. 3. Tab. V. and Fig. 8." and 11. Tab. 
IV. 
