A SYSTEM OF 
ig8 
working of this ftone may be mixed with tfid 
common fait, for the diftillation of the muriatic 
acid* 
SECT. XCVIL 
The Sixth Order.' 
The Fliiors Fluores Minerales, Suet. Flujf- 
arter. Germ. Flujf-arten, 
Thefe are commonly called fluxing vitref- 
cent, or glafs fpars, becaufe moft part of them 
have a fparry form and appearance : they are,i 
however, often met with in an indeterminate 
figure. 
Thefe are only known in an indurated 
ftate, and diftinguifh themfelves from the 
other earths, by the following chara6lers. 
1. They are fcarce harder than a calcareous 
fpar, and confequently do not ftrike fire 
with the fteel. 
2. They do not ferment with acids, neither 
before nor after calcination, notwithftand- 
ing a phlogifcon or an akali had been 
added in the calcination. 
3. They do not melt by themfelves, but 
only fplit to pieces when expofed to a 
ftrong fire f. But, 
■4. In mixtures with all other earths, they are 
very fufible, and efpecially when they are 
* I have adopted the nafne of Fluors, in Engliih, to this 
order. D. C. 
•|' There may, perhaps, be feme fiuors that are pretty re- 
fraftory in the hre, fo as not to be melted:, however, all 
thofe which I have tried, have melted pretty eafiiy by the 
blow-pipe ; but I have always taken great care in thefe es!- 
periments, that they might not dy away before they were- 
keated thro ugh » ^ 
blended 
