A SYSTEM OF 
I46 
5. After being refined, it fhoots into irregukr 
figures : but the cryftals, which form them- 
felves after the firfl operation, and are call- 
ed "Tincal^ confift of fiat oftagonal prifms^ 
flat at the extremities, and with their an- 
gles cut off or truncated 
It is yet unknown of what fubflance the Eaft-Indians and 
Chinefe prepare the borax. The unrefined, which is brought 
to Europe under the name of tincal, looks like foft foap, is 
fat, and covers or encrufts the borax criftals. The mine- 
mailer Mr. Swab, who has had an opportunity of making 
experiments upon this tincah has publilhed them in the Afts 
of the Royal Academy of Scieuces at Stockholm for 1756. He 
fays, that he has found in it a martial earth, and a fat fub- 
llance, which, to fmell and other circumftances, comes nearell 
to a mineral fat : as likewife, that pure borax does not yield 
any hepar fulphttris, when united with a phlogifton and a vi- 
triolic acidj from which he concludes, that borax is prepared 
from its own particular mineral fubllance. 
ProfelTor Pott and Mr. d’Henouviile have very carefully 
examined the refined borax ; and from their experiments, 
which have been publilhed, it is evident, that it is of a par- 
ticular alcaline nature : however, there yet remains to know 
for certain, from what it is prepared by the Indians : for, if 
it is produced from a mineral fubllance, as is very probable, 
there mull exill other mixtures and compolitionsa which are 
yet unknown to the learned world. 
I have alfo found in the tincal fmall bits of leather, bones 
and fmall pebbles, whence there is no certainty to be con- 
cluded on from its examination ; but, if it Ihould happen, 
that it is prepared from animal fubllances, it mult be allowed, 
that nature has formed an alcaline fait in the animal king- 
dom, which anfwers to the fixed acid fait in the human urine, 
called fal fujibile mkrocofmicum^ and which has been firll ac- 
curately delcribed by Mr. MargrafF, in the Memoirs of the 
A^cademy of Berlin. 
Some years ago a report was propagated from Saxony, that 
fomebody had there discovered a fubllance out of which borax 
could be made, and alfo the art of preparing it : but nothing 
more has ever tranfpired fince, than that the author Ihewed it 
in fecret to his friends, and gave a defeription of it, which 
only was intended to miflead them, if he really did polTefs 
the art. 
SECT. 
