ACTION OF SALTS. 113 



Peat ashes abound in carbonate, sulphate, and 

 especially phosphate of lime. Free alkali may be 

 always traced in peat ashes ; but alkali exists in it, 

 rather as silicate, as in leached ashes. Anthracite 

 coal ashes contain carbonate of lime, alumina, and 

 oxide of iron. It is good, so far as these abound. 



The above are calculated on the analyses of Ber- 

 their, who has detected soda in the ashes of many 

 plants. The elements are. stated singly ; because 

 we have thus at one view, the amount of each, and, 

 it is the base chiefly w 7 hich acts. The agricultural 

 value of ashes may be determined by reference to 

 these tables. In what state these elements may be 

 combined in plants, we can only determine theoret- 

 ically. Thus, the phosphoric acid, by its affinities, 

 would be united in the hard woods as above, with 

 the lime and iron — forming in each 100 parts of the 

 insoluble portion of ashes, phosphate of lime, 5*40 ; 

 phosphate of iron, 1*86. 



The composition of the insoluble part of ashes 

 gives nearly the constituents of leached ashes. 

 If the soap-boiler's process was as perfect as that 

 which the chemist employs — still his leached ashes 

 would show more lime, than the above tables, be- 

 cause he always employs a portion of lime to make 

 his ley caustic. This is a variable portion ; whatev- 



10* 



