164 
POPULAR SCIENCE REVIEW. 
When boronatrocalcite is moderately pure, it is first ground 
and subsequently dissolved in water, with the addition of an 
■amount of carbonate of sodium sufficient to effect the decompo- 
sition of the calcic carbonate present. 
The solution is subsequent^ heated, and the carbonate of 
•calcium allowed to subside, when the liquor is drawn off, and, 
•after concentration, borax is obtained by crystallization. 
Unfortunately, this mineral often contains notable quantities 
of gypsum, which transforms an equivalent amount of carbo- 
nate of sodium into Glauber salt, a relatively valueless pro- 
duct. This salt is also frequently present in the material 
operated upon, and thus materially adds to the difficulty of 
treatment. In order to avoid these difficulties, it has been 
proposed to treat native boronatrocalcite with sufficient sul- 
phuric acid to transform the whole of the carbonate of calcium 
into gypsum, and to liberate boric acid, to be subsequently 
saturated by carbonate of sodium. Boronatrocalcite has also 
been treated with excess of hydrochloric acid, in order to obtain 
crystallized boric acid, but neither of these processes has 
hitherto afforded satisfactory commercial results. 
The comparatively recent discovery of large quantities of 
this substance in Nevada will, no doubt, eventually to some 
•extent, affect the Tuscan producers of boric acid ; but the fact 
that crude boronatrocalcite varies considerably in its composi- 
tion, and that it is found in situations in which its local 
treatment would be almost impossible, has hitherto prevented 
this mineral from being extensively employed as a source 
•of commercial borax. 
