CHAP. XVI, 
Borax. 
B ORAX is a faline Subfiance, very 
difficult in Solution unlefs in boiling 
Water, and even then requiring, accord¬ 
ing to Boerhaave , twenty Times its own 
Weight. 
When a Drop is given to be examined by 
the Microfcope, if it be held too long over 
the Fire no Cryflals will fhoot, but it will 
harden upon the Slip into a.tranfparent Mat¬ 
ter much refembling Glafs. The belt Way 
is to give it a brifk Heat for about one Second 
of Time, and then applying it, the Cryflals 
will quickly be feen forming about its Edges, 
as in Plate III. N° II. where their Begin¬ 
ning and Progrefs are fo reprefented as to 
need no farther Defcription. 
In the middle Parts of the Drop no Cry- 
Hals at all arife, but there are feveral trans¬ 
parent circular Figures, that from mere 
Specks grow gradually bigger, till they re¬ 
ferable imall Drops of Oil floating upon the 
Surface of Whiter: thefe ajfo are fhewn in 
the Drawing. 
This Salt is faid to be found in India, 
Berfia, and Tartary, and to be brought 
from thofe Countries rough and foul, in 
Lumps 
A 
