14 
ON PHOSPHATE OF AMMONIA. 
establish its character, and confirm the experiments which 
have thus far been made, it will no doubt be added to the 
list of officinals in the next edition of our National Phar- 
macopoeia. 
This salt is readily prepared by the direct union of phos- 
phoric acid and ammonia, with which it forms three combi- 
nations, containing one, two, and three equivalents of ammo- 
nia. The first salt is composed of one equivalent of acid, one 
of ammonia, and two of basic water : the second salt of one 
equivalent of acid, two of ammonia, and one of basic water ; 
and the third salt of one equivalent acid, three of ammonia, 
and no basic water, being salts of the tribasic phosphoric 
acid in which the basic water is partially or wholly dis- 
placed by ammonia. The first mentioned salt is called by 
some authors the biphosphate — the second salt, the neutral 
phosphate, and the third salt the subphosphate. It is the 
second salt or neutral phosphate that it is designed to em- 
ploy as a remedial agent. 
Of the two methods for obtaining phosphoric acid — by the 
action of nitric acid on phosphorus, and by the decomposi- 
tion of calcined bones — the latter is preferred on account of 
its safety and cheapness. The following is the usual for- 
mula, viz: 
Take of Bone burnt to whiteness and powdered 10 lbs. 
Sulphuric acid 6 lbs. 
Mix them in a stone-ware vessel, and add one gallon of 
water — digest for three or four days, frequently stirring, and 
add a gallon of boiling water — strain through linen, gradual- 
ly adding more boiling water until the liquid passes without 
much taste. The sulphuric acid acts upon the lime of the bone- 
earth, effecting a partial decomposition, the greater portion of 
its phosphoric acid is liberated, which acts as a solvent for the 
remaining portion of bone-earth, and remains in the strained 
liquor as a superphosphate of lime contaminated with a 
portion of sulphate of lime. The acid solution is concen- 
trated to one gallon, and, by cooling, deposits the sulphate 
