340 
BORACIC ACID. 
Boracic acid may also be obtained by dissolving borax in 
hot water, and adding half its weight of oil of vitriol. As 
the solution cools, crystals of boracic acid (retaining a little 
sulphuric acid) are deposited, which must be well washed. 
Or borax may be decomposed by hydrochloric acid, by which 
a purer boracic acid is procured. 
Properties.™ Crystallized boracic acid occurs in the form 
of white, transparent, pearly, hexagonal scales, which are 
odorless, have a weak, scarcely acid, taste, and communicate 
a wine-red tint to litmus. At 60° the crystallized acid re- 
quires 25.66 times its weight of water to dissolve it, but only 
2.97 times at 212°. It dissolves readily in spirit of wine. 
When sufficiently heated it evolves its water of crystalliza- 
tion, melts, forming a transparent liquid, which, by cooling, 
becomes a brittle glass {vitrified boracic acid.) 
Characteristics. — An alcoholic solution of boracic acid 
burns with a beautiful green flame. A hot aqueous solution 
of the acid renders turmeric paper brown, like the alkalis. 
(Faraday, Quarterly Journal of Science, vol. ix. p. 403.) 
Before the blowpipe, boracic acid fuses, and forms a glass 
which may be tinged blue by chloride of cobalt, and rose-red 
by the terchloride of gold. A mixture of one part of vitrified 
boracic acid, finely pulverized, two parts of fluor spar, and 
twelve parts of oil of vitriol, evolves, by heat, the fluoride of 
boron, recognised by its forming dense white fumes in the 
air, and by its charring paper, w r ood, &c. 
Composition. — The following is the composition of boracic 
acid: — 
Atoms. Eq.Wt. Per Ct. Berzelius. /toms. Eq.Wt. Per Ct. Berzelius. 
Boron 1 10 29.41 31.18 D 7 c f d ° raCiC } 1 34 55 ' 74 56 
Oxygen 3 24 70.59 68.82 Water 3 27 44.26 44 
DryBoracic^ 34 100 . 00 ^ Crystal,^ j [ " ~^ ^ ~ 
Physiological Effects and Uses. — Though sedative 
properties were formerly ascribed to this acid, it is probably 
inert, or nearly so. Cullen (Materia Medica, p. 341,) gave 
