250 § 128. ANALYSIS OF ASHES. 



water, and heat the mixture to boiling. Filter the solu- 

 tion into a graduated cylinder, and wash the insoluble 

 residue with sufficient water to make the volume of the 

 solution exactly 100 c.c, when properly cooled. Titrate 

 10 c.c. of this solution with the normal acid (§ 44,/*), 

 subtract 0.3 c.c. for the excess of lime, and then multiply 

 the number of cubic centimetres required by 10, for the 

 per cent of potassic carbonate. 



Peat and Coal Ashes are usually very poor in alkalies 

 and phosphoric acid. Their agricultural value depends 

 more particularly on. the amount of calcic sulphate 

 (gypsum), and calcic carbonate and phosphate, which they 

 contain. 



Many kinds of peat leave ashes that are rich in gypsum ; 

 in such cases it is well to boil about 2 grms. of the ashes 

 an hour, with a solution of 6-8 grms. of sodic carbonate, 

 and determine sulphuric acid in the aqueous solution so 

 obtained, and lime in the hydrochloric solution of the 

 residue insoluble in water. 



