ON A NEW BORATE OF SODA. 
175 
borate of soda and chloride of ammonium, and the borate 
of ammonia parts with ammonia even at a low temperature 
like other ammoniacal salts (that it is decomposed at a high 
temperature, with elimination of ammonia, is well known;) 
or the chlorine of the sal-ammoniac may deprive the borax 
of a part of its soda, forming a corresponding amount of 
chloride of sodium, ammonia being thereby liberated, while 
with the remainder of the soda a salt might be formed with 
a larger amount of boracic acid. It seemed to me worth 
the trouble to ascertain which of these suppositions was 
true ; for if the latter happened, we might expect to obtain 
the long-missed quadriborate of soda on employing the two 
bodies in suitable proportions. The following are the salts 
of boracic acid with soda known at present: — NaO, BO 3 ; 
NaO,2BU 3 ; NaOeBO 3 . There are evidently some mem- 
bers missing in this series. 
Chloride of ammonium was mixed with crystallized borax 
in the proportion of 2 equivs. of the latter to 1 of the for- 
mer ; the whole being dissolved and boiled as long as am- 
moniacal vapours were given off. The solution was then 
filtered and very gradually evaporated. This experiment 
was frequently repeated, but each time the same evil occur- 
red, that the first crop of crystals were borax ; and on 
further evaporation, if the temperature had been somewhat 
too high, the solution became syrupy and deposited no more 
crystals. But on very slow evaporation, some crystalline 
crusts separated at the bottom and on the surface, which 
agreed in their external characters and in their chemical 
reactions. After being rinsed with water and recrystallized 
once, they were obtained nearly free from chlorine ; the 
mother liquor always contained a large quantity of chloride 
of sodium. These crusts were very hard, milk-white or 
vitreous, shining, and presenting upon the surface an agglo- 
merate of minute intimately-adherent crystals, but exhibit- 
ing on fracture a radiate structure. They contain much 
water, which escapes on the application of heat, without, 
