[ i84 ] 



twelfth part of each of the fupplements S. W. F. C. and -S', 



.1, • • ^1 ■ r 1017,66 o, , 100 o , 10 o 



thr.t IS in this cafe — 1^— =84,405 + = 8,333+ —= 8,333 



12 12 12 



+ — = r + _= 0,3333 = 95 grains in all — then 480 — 95 = 385 

 12 12 



grains will remain, and reprefent the mere earthy matter in an 



ounce of the foil. 



9"' Let this remainder be gradually thrown into a Florence flaflc 

 holding one and an half as much fpirit of nitre as the earth 

 weighs, and alfo diluted with its own weight of water ; (the acids 

 employed fhould be freed from all contamination of the vitriolic 

 acid) ; the next day the flaik with its contents being again weigh- 

 ed, the difference between the weights of the ingredients and the 

 weights now found will exprefs the quantity of air that efcaped 

 during the folution ; — thus in the above cafe the earth weighing 

 385 grains and the acid 577,5 grains, and the water 577,5 grains, 

 in all 1 540 grains, the weight after folution fhould alfo be 1540 if 

 nothing efcaped ; but if the foil contains calcareous matter a lofs 

 will always be found after folution j let us fuppofe it to amount 

 to 60 grains. 



The weight of air that efcaped furnifhes us with one method of 



eftimating the quantity of calcareous matter contained in the earth 



elTayed, for mild calx generally contains 40 per cent of air ; then 



if 40 parts air indicate 100 of calcareous matter, 60 parts air will 



indicate i 50*. 



io°- The 



* I tate no account of magnefia, as in agriculture I believe It of little importance. 



^ 



