t 293 1 
S E C T. XXII. 
‘The quantity of thefe two falts required Cor an 
‘experiment is almoft the fame as the Sal Sod^e 
(Sedt. XX.) 3 but as thefe falts are criftallifed, and 
confequently include a great deal of water, parti- 
-cularly the borax, their bulk is confiderably re- 
duced when melted, and therefore a little more of 
thefe may be talcen than the before- mentioned 
.quantity. 
SECT. XXIII. 
Both thefe falts, (Sed. xxi.) when expofed to 
the flame of the Blow pipe, bubble very much 
land foam before they melt to a clear glafs, but 
more fo the borax, which for the moft part de- 
pends on the water they contain : And as this 
would hinder the affayer to make due obfervations 
on the phoenomcna of the experiment, the fait 
which is fo be ufed, muft flrfl: be brought to a clear 
.glafs, (Se6l. xxi.) before it can ferve as a flux; 
it mufl: therefore be kept in the fire until it is 
. become fo tranfparent that the cracks in thexhar- 
coal may be feen through it. This done, whatlb- 
ever is to be tried, is put to it, and the fire 
.continued. 
SECT. XXIV. 
Here it is to be obferved, ithat for the aflays 
.made with any of thefe two fluxes (Seel, xxii ) 
on mineral bodies, no larger pieces of thefe 
mufl; be taken, than that altogether they may 
■keep a globular form upon the charcoal ; becaufe 
then it may be better difliinguiflicd in what man- 
ner the flux upon the matter during the ex^ 
U 3 ' periment: 
