OXALATES, NITRATES, PHOSPHATES, SULPHATES, AND CHLORIDES. 
G3 
First Class. 
Monobasic phosphate of water (metaphosphate of water) H P. 
Monobasic phosphate of soda (metaphosphate of soda) NaP. 
Second Class. 
Bibasic phosphate of water (pyrophosphate of water) . IT 2 P. 
Bibasic phosphate of soda and water (bipyrophosphate 
of soda) Na II P. 
Bibasic phosphate of soda (pyrophosphate of soda) . . Na 2 P -f- 10 H. 
Third Class. 
Tribasic phosphate of water (common phosphate of water) H 3 P. 
Tribasic phosphate of water and soda (biphosphate of 
soda) . NaH 2 P + 2lT. 
Tribasic phosphate of soda and water (phosphate of soda) Na 2 H P + 24 H. 
Tribasic phosphate of soda (subphosphate of soda) . . Na 3 P + 24 II. 
Tribasic phosphate of soda, ammonia, and water (micro- 
cosmic salt) Na NH 4 IT P T- 8 H. 
Tribasic phosphate of magnesia and water (phosphate 
of magnesia) . Mg 2 H P + 2 H + 12 H. 
Tribasic phosphate of magnesia and ammonia (ammo- 
niaco-magnesian phosphate) Mg 2 NIT 4 P + 2 H + 10 H. 
It is my object to get rid of the trivial names pyrophosphates, metaphosphates, and 
common phosphates, which have tended to keep up an erroneous impression that the 
phosphoric acid is of a different nature in these classes of salts, or is modified in some 
way unknown. This notion has arisen from the pertinacity with which phosphoric 
acid continues combined with a constant number of atoms of base, whether it be one, 
two, or three, although the base itself be repeatedly changed by decomposing the 
original combination. But this is an occurrence quite analogous to the formation of 
different sets of sulphurets or of chlorides, when we decompose two or more different 
oxides of the same metal, such as the oxide and suboxide of mercury, by sulphuretted 
hydrogen or by muriatic acid. The metal continues in the same relative state of sa- 
turation throughout a series of such decompositions ; and so does the phosphoric acid, 
because in both cases the decomposition is effected by an equivalent substitution. 
A difficulty occurs in naming two members of the tribasic class, so as to distinguish 
them from each other, namely, the biphosphate of soda and phosphate of soda, both 
of which contain soda and water as base. But this difficulty is obviated by placing 
