328 Dr. Pearson on expectorated Matter. 
monia produced a milky liquid — no effect was observed from 
tartaric acid. -“There being a precipitation with caustic or pure 
ammonia, as well as with potash, and with the carbonates of 
the alkalies, it was supposed magnesia was present : and the 
dissolution of this precipitate in muriatic acid, and in acetous 
acid, gave no precipitate with oxalic acid. Some of the mu- 
riatic dissolution, previously to precipitation with oxalate of 
ammonia ( j ), being evaporated to dryness, the residue was 
ignited; but if magnesia was present, as well as lime, it was in 
too small quantity to be distinguishable from the lime, by 
composing sulphate. The precipitate now under examination, 
was certainly not mere magnesia, for it melted into an opaque 
globule under the blow-pipe — it was not phosphate of lime, 
for with sulphuric acid, a somewhat bitter and sour substance 
was compounded, which afforded a precipitate with ammonia, 
but none with oxalate of ammonia. It was a phosphate not 
only on account of its fusibility, but because a curdy appear- 
ance was occasioned by the mixture just mentioned, with sul- 
phuric acid, on adding it to lime water. Neither was it soluble, 
like phosphate of lime, in phosphoric acid. The quantity of 
this precipitate was too minute for decisive experiments, but 
from those related, it seems probable that it was phosphate of 
magnesia, which was dissolved, as will appear presently, in 
phosphoric acid, and precipitated by ammonia. 
(k). The residuary liquid (g), after the precipitation by ox- 
alate of ammonia, being evaporated to dryness, was easily 
ascertained to be phosphate of ammonia, with indications of a 
minute proportion of sulphate. 
(z). It remains only to notice the indissoluble matter in 
