in the fixed principles of the egg during incubation 383 
phate of magnesia and ammonia, after being washed with dis- 
tilled water, was dried and weighed. The alkaline solution, to- 
gether with the washings of the earthy phosphates, were then 
evaporated to dryness, and exposed to a low red heat ; and 
the weight of the saline residuum being accurately noticed, 
the whole was again dissolved in distilled water. A few drops 
of nitric acid being now added to neutralize the excess of al- 
kali present, nitrate of barytes was dropped into the solution 
as long as any precipitate fell. The precipitate was obtained 
by decanting off the solution as before, and, after being well 
washed, its weight ascertained : from this the quantity of 
sulphuric acid present was determined by calculation.* To 
the solution, thus freed from sulphuric acid, nitrate of ba- 
rytes, and afterwards ammonia, were added. The phosphate 
of barytes thus obtained was collected, washed and weighed 
as before, and the quantity of phosphoric acid present obtained 
by calculation.-f Nitric acid was again added in slight ex- 
cess to the original solution, and nitrate of silver dropped into 
it as long as any precipitate fell ; from the chloride of silver 
obtained, the quantity of chlorine present was estimated.^ 
Lastly, the weights of the sulphuric and phosphoric acids and 
chlorine were added together, and their amount subtracted 
from the weight of the alkaline residuum formerly obtained 
by evaporation, the remainder, of course, indicated the quan- 
* On the supposition that the weight of the atom of sulphuric acid is 50, and that 
of barytes 97.5, oxygen being 10. 
f On the supposition that the weight of the atom of phosphoric acid is 35, that 
of oxygen being xo. 
X On the supposition that the weight of the atom of chloriae is 45, and of silver 
137.5, that of oxygen being 10. 
