t 235 3 
;dbove defcribed manner (Se6i:. xxii. et feq,) it is* 
‘Cafily feen whether it is quickly difiblved, becaule 
in that cafe an effervefcence ariles, w^hich lalls till- 
the v/hole is diflblved ; or whether this is flowly 
done, in which cafe few and fmall bubbles only 
rife from the matter : Likewife, if it cannot be 
diffolved at all, becaufe then it is obferved only to 
turn round in the flux without the leafb bubble, 
and the edges look as fliarp as they were before. 
SECT. XXVJ. 
In order further to illuftrate what has been faid 
about thefe experiments, I will mention fome * 
inftances out of the Mineralogy, concerning the 
€ffed:s of borax upon the mineral bodies, viz. 
1. The calcareous fubftairces, and all rhofe 
Hones which contain any thing of lipie in their 
compofition, diflblve readily and with effervefcence 
in the borax : This effervefcence is the more vio- 
lent, the greater the portion of lime contained in 
the Hone. This reafon, however, is not the only 
one in the gypfum, becaufe both the conflituents 
of this do readily mix with the borax, and there- 
fore a greater effervefcence arifes in melting gyp- 
fum with the borax, than lime alone. 
2. The Siiice^ do not diflblve, unlefs fome few, 
which contain a quantity of iron. 
The Argillaceje.> when pure, are not afled 
upon by the borax *, but when they are mixed with 
fome heterogeneous bodies, they are diflblved, 
though very flowly ; fuch is for inftance the Stone 
Marrow, the Common Clay, &c. 
4. The Granatem, Zeolites, and Trapp, diiTolve 
but 'flowly. 
5. The Finores, Afbeflins, and Micace^, dif- 
folve for the mod part very eaflly, and fo forth. 
^ U 4 S £ C T. 
