ANALYSIS OF SOILS. $£ 



JC. Mqdeof afcertaining the Quantity of infoluhle finely divided 

 Animal and Vegetable Matter, 



After the fine matter of the foil has been a&ed upon by Ignition in ati 

 muriatic acid, the next procefs is to afcertain the quantity of deftroys vege- 

 iinely divided infoluble animal and vegetable matter that it table and animal 

 contains. * uttcrs - 



This may be done with fufficient precifion, by heating it to 

 flrong ignition in a crucible over a common fire til! no black- 

 jiefs remains in the mafs. It mould be often ftirred with a 

 metallic wire, fo as to expofe new furfaces continually to the 

 air; the lots of weight that it undergoes denotes the quantity 

 of the fuhfiance that it contains deftructible by fire and air. 



It is not poffible to afcertain whether this fubftance is wholly 



animal or vegetable matier, or a mixture of both. When the 



fmeli emitted during the incineration is fimilar to that of burnt The fmell fhews 

 r , . . ....'. r r , whether it be 



leathers, it is a certain indication or tome animal matter ; an ; ma i Qr vegc , 



and a copious blue flame at the time of ignition, almoft always tabic. 

 denotes a confiderable proportion of vegetable matter. In 

 cafes when the experiment is needed to be very quickly per- 

 formed, the deftruclion of the decompofible fubftances may- 

 be aflifled by the agency of nitrate of ammoniac, which at the 

 time of ignition may be thrown gradually upon the heated 

 mafs in the quantity of twenty grains for every hundred of 

 rehdual foil. It affords the principle neceflary to the combuf* 

 tion of the animal and vegetable matter, which it caufes to be 

 converted into elaftic fluids ; and it is itfelf at the fame time 

 tlecompofed and loft. 



XI. Mode of feparating aluminous andfilicious Matter 

 and Oxide of Iron. 



The fubftances remaining after the decompofition of the ^e refidual 

 .iii-i 11 . . , tilex, aluminc 



vegetable and animal matter, are generally minute particles and oxide of 



of earthy matter, containing ufually alumine and filex with iron Separated. 



combined oxide of iron. 



To feparate thefe from each other, the folid matter mould 



be boiled for two or three hours with fulphuric acid, diluted 



with four times its weight of water ; the quantity of the 



acid mould be regulated by the quantity of folid refiduum D ! ,ute falphunc 



to be aaed on, allowing for every hundred grains two drachms two &ft! " P ** 



m one hundred and twenty grains of acid. 



The 



