C 26 7 ] 
thus it happens that we have fuch figur’d Codies from 
the Spar, which, without thofe Salts, would fhew 
us no fuch Shoots as we call Cornifh Diamonds, but fix 
quietly into Sheets, and even Plates, or drop down 
where-ever its own Weight would carry it. 
What fort of Salt it is, which inclines Spar to this 
hexagonal Form, is the next thing to be inquired into ; 
and mod probably will appear to be that of Nitre, if 
we confider that the Rcfemblance betwixt the Figure 
of what we call Cornijh Diamonds, and that of the 
pure unmix’d Nitre, is fo great, that no two things 
can be more exactly alike. “ The known Figure of 
“ Nitre, fays Grew ( Cofmol . p. if.) is a fexangular 
“ Prifm.” tc Particulas nitri Lijierus deprehendit 
ec fexangulas, tenues, longas, lateribus parallelo- 
“ grammis, & ex altera parte in pyramidale acumen 
“ definentes.” Fhyf. Cler. 8w, tert. Edit. p. 150 . 
This exa& Rcfemblance is lufficient to 'make us con- 
jecture, that thefe fparry Productions may owe their 
general Figure to a nitrous Salt, which exerted itfelf 
at the time when the Juice of Spar became Stone ; and 
I fhall endeavour to fupport this Conjecture only by 
one Authority, which is that of the curious, and, in 
the Studies of Natural Hiftory, indefatigable Linnaus, 
which he favoured me with in Anfwer to fome Que- 
ries, jointly with the Opinion of the prefent Dr. 'John 
Frederick Gronovius of Leyden. “ The Origine of 
“ thole Crvftals (18) is a moft intricate thing j but 
“ you may conclude — quod otnnis cryftallizatio a 
LI 2 . “ f ale. 
Grew ( Cofmol . p. 14.) after talking of the Regularity of Forms, and 
the Salts of Bodies, proceeds thus : ‘ c Arguing (fays he) that the Atoms 
cc of the lapidific, as well as of the faline Principle, being regular, do 
<c therefore concur in producing regular Stones.” 
(18) Cor?iijb Diamonds, fent to Dr. Gronovius from Cornwall. 
