130 
mospheric pressure on the other hand causes the formation 
of the new compound : tricalcium phosphate sulphite, 
Ca 3 PA, SO,, 2H,0, as a crystalline precipitate which is dis- 
tinguished from the above mentioned mixtures of dicalcium 
phosphate and calcium sulphite by its great stability. It 
claims more general interest as being an active manure and 
disinfectant. The unusual composition of this substance 
made it desirable to prepare corresponding compounds of 
other metals, but all attempts in that direction have been 
unsuccessful. 
Dicalcium hydric phosphate is readily soluble in water 
charged with sulphur dioxide. From the solution the 
original phosphate can be easily obtained. 
b. Trimagnesium-, dimagnesium-, and magnesium-am- 
monium- phosphate are dissolved in large quantities by 
water charged with sulphur dioxide ; the first two Avithout 
decomposition, but if an excess of the latter has been used, 
dimagnesium hydric-phosphate is left undissolved. All 
these solutions have a great tendency to deposit dimagne- 
sium hydric phosphate in crystals. 
c. Tri- and di- manganese phosphate are very soluble in 
sulphur dioxide and Avater. Both solutions give crystals 
in vacud, consisting principally of dimanganese phosphate, 
but by boiling, precipitates of trimanganese phosphate are 
formed. 
cl. Copper phosphate is soluble, although in smaller quan- 
tity, in an aqueous solution of sulphur dioxide without 
decomposition. The solution deposits at summer tempera- 
ture in course of time crystals of cuprous and cupric-sul- 
phite, and by boiling, cupric phosphate. 
e. Uranium phosphate is very slightly soluble in Avater 
charged with sulphur dioxide. The phosphate of the 
original composition separates again from tho solution after 
the removal of the sulphur dioxide. 
/. Crystals of trisodium phosphate absorb sulphur 
