METHODS OF ANALYSIS. 253 



weight of the precipitate, as is sometimes done : 

 the former being considered the most reliable. 



METHOD FOR ACTUAL AMMONIA AND POTASH. 



Substance = 50 grammes. 



Fluid = 250 c.c. 



Fluid taken = 25 c.c. == 5 grammes substance. 



The substance in an evaporating dish was 

 treated : first, with small quantities of water at 

 60 to 70 ; then boiled successively in water 

 acidulated with hydrochloric acid; and finally, 

 washed on a filter with boiling water, till the 

 filtrate measured nearly 250 c.c. 



The ammonia was determined according to 



SCHLOESING'S PROCESS. 



Strength of Soda Solution, 3.06 c.c. = 1 c.c. Normal Sulphuric Acid. 



The potash was determined as potassio-bichlo- 

 ride of platinum. 



METHOD FOR TOTAL PHOSPHORIC ACID. 



Substance = 20 grammes. 



Fluid = 1000 c.c. 



Fluid taken = 50 c.c. = 1 gramme substance. 



The hydrochloric acid solution, with the addi- 

 tion of several drops of concentrated nitric acid, 

 was evaporated completely to dry ness, and the 

 residue treated with dilute hydrochloric acid. To 

 the solution thus obtained, there was added; 

 first, citric acid, in quantity sufficient; then 

 ammonia ; then, acetic acid, each slightly in ex- 

 cess ; and finally, to the nearly boiling solution, 



