in the Fixed Principles of the -Egg daring Incubation, i'i 
canting 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 barytes, and afterwards 
ammonia, were added. The phosphate of barytes thus obtain- 
ed was collected, washed and weighed as before, and the quan- 
tity of phosphoric acid present obtained by calculation. Nitric 
acid was again added in slight excess 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 chlo- 
rine present was estimated. Lastly, The weights of the sul- 
phuric 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 quantity of potash and soda, and carbo- 
nates of potash and soda present. Finally, the proportion of 
the earthy phosphates to one another was determined, and the 
quantities of the bases and acid obtained by calculation. 
The yolk of the egg is exceedingly difficult of combustion ; 
and, indeed, without proper precautions, cannot be burnt at all, 
on account of the large quantity of phosphorus contained in it, 
which* by undergoing a partial combustion, forms a glassy coat- 
ing, that effectually excludes the contact of the air from the 
coal, and prevents its farther combustion. After a variety of 
attempts, the following were the two methods employed. The 
yolk of an egg which had been boiled hard, and dried by ex- 
posure to the air, was rubbed in a mortar with a quantity of 
bicarbonate of potash. The mixture was then introduced into 
a platina crucible, and exposed to a strong red heat, till the 
flame had ceased to escape from a small hole in the lid. The 
crucible being now removed from the fire, its contents, when 
cold, were again pulverised in a mortar with nitre. This mix- 
ture was then introduced, a little at a time, into the covered 
crucible, till the whole was burnt. To the residuum distilled 
water was added, which of course took up every thing but the 
earthy phosphates, which were separated and weighed, while 
the alkaline solution, like that before mentioned, obtained from 
the albumen, was submitted to the action of the appropriate re- 
agents, and thus the quantities of the different acids present 
