1^6 A TREATISE ON THE CONNECTION OF 



table matter, appearing in the soil in an iindecayed state. 

 Chemical tests, in either of these cases, are unneces- 

 sary. When it may be requisite, however, to ascertain 

 the presence or proportion of it in clayey or other 

 soils, in which, from colour or extreme division of parts, 

 it is less apparent, it is to be done in one or other of the 

 following methods : 



By properly drying and weighing a certain weight of 

 mould, and then submitting it to such a degree of heat 

 as will consume the vegetable or carbonaceous matter to 

 ashes : at the same time, the heat must not be such as 

 will disengage the fixable air from any cdcareous matter 

 ,or magnesia that may be contained in the mould or 

 soil submitted to trial. The difference in weight between 

 the dry mould, and that which is thus submitted to the 

 adtion of fire, ^^■ill be tlie proportion of vegetable or 

 carbonaceous matter. 



It is likewise to be done by melting some salt-petre in 

 an iron laddie, bringing the salt-petrc to a red fusion, 

 and then dropping into it, by little and little at a time, 

 the earthy matter, taking care previously to dry it 



tho- 



