24)4i Mr. Home’s Observations on the Structure oj 
water, precipitated lime from lime water, in the state of phos- 
phate. 
To another portion, solution of acetite of lead was added, 
and caused an immediate precipitation of a white matter, which, 
when dried and sprinkled on burning charcoal, produced a light 
and smell like phosphorus ; it, moreover, was soluble in nitrous 
acid, and was thus to be distinguished from muriate or sulphate 
of lead. 
Experiment n. Some of the raspings of enamel were dis- 
solved by digestion in nitric acid, and, when the solution had' 
been diluted and filtrated, it was saturated with carbonate of 
ammoniac. The precipitate thus produced was collected, and 
edulcorated in a filter. The small excess of carbonate of ammo- 
niac, in the filtrated liquor, was saturated with acetous acid ; after 
which, the phosphoric acid was precipitated, by solution of acetite 
of lead. Upon examining the first precipitate, or that produced 
by the carbonate of ammoniac, it was found (contrary to ex- 
pectation) that it was still composed of lime, combined with a 
portion of phosphoric acid, instead of carbonic acid, which 
might have been supposed. 
To effect, therefore, a complete separation of the two ingre- 
dients, (lime and phosphoric acid,) acetous acid was poured on 
the precipitate, by which it was immediately dissolved. The 
whole of the phosphoric acid was then separated from this so- 
lution, by acetite of lead ; after which, lest any lead should be 
present, the liquor was saturated with pure or caustic ammoniac, 
and the lead was separated by a filter : lastly, the lime which 
remained dissolved, was precipitated (in the state of carbonate) 
by carbonate of ammoniac. 
The enamel has been supposed, not a phosphate but a car- 
