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to the mouth ; the difference between the weight of 

 the soil and that of the water, will give the result. 

 Thus if the bottle contains four hundred grains of 

 water, and gains two hundred grains when half filled 

 with water arid half with soil, the specific gravity of 

 the soil will be 2, that is, it will be twice as heavy as 

 water, and if it gained one hundred and sixty-five grains, 

 its specific gravity would be 1825, water being 1OOO. 



It is of importance, that the specific gravity of a 

 soil should be known, as it affords an indication of 

 the quantity of animal and vegetable matter it con- 

 tains ; these substances being always most abundant 

 in the lighter soils. 



The other physical properties of soils should 

 likewise be examined before the analysis is made, as 

 they denote, to a certain extent, their composition, 

 and serve as guides in directing the experiments. 

 Thus siliceous soils are generally rough to the touch, 

 and scratch glass when rubbed upon it ; ferruginous 

 soils are of a red or yellow colour j and calcareous 

 soils are soft. 



1. Soils, though as dry as they can be made by 

 continued exposure to air, in all cases still contain a 

 considerable quantity of water, which adheres with 

 great obstinacy to the earths and animal and vegeta- 

 ble matter, and can only be driven off from them by 

 a considerable degree of heat. The first process of 

 analysis is, to free the given weight of soil from as 

 much of this water as possible, without in other res- 

 pects, affecting its composition ; and this may be done 

 by heating it for ten or twelve minutes over an Ar 



