14 Experiments and Observations 
The phosphate of magnesia consists of 
57.5 acid or 100 acid 
42.5 mag. 70 mag, 
100 
Phosphate of alumine. 
This salt may be formed by mixing a solu- 
tion of common alum with phosphate of soda ; 
phosphate of alumine falls down and sul- 
phates of soda and potash remain in solution 
in the liquor. It consists of 
60.5 acid or 100.acid 
39.5 alumine 64 alumine 
100 
All these earthy phosphates resemble that 
of lime, and are soluble in an excess of acid, 
but whether in the same proportions as lime 
J have not yet ascertained, 
Phosphate of potash. 
I have not had time to examine the various 
compounds of phosphoric acid and potash ; 
-but from some trials 1 have reason to believe 
they will be found very nearly to agree in cha- 
racter with the phosphates of soda already 
described, 
