328 SyLVA AMERICANA. 



attracting a very large portion of vegetable nourishment from the 

 atmosphere, and of producing its crops with comparatively little 

 labor and expense. 



Of Discovering the Qualities of a Soil Mechanically 



and Empirically. 



The physical properties of soils and some of their most 

 important constituents relatively to the cultivator, may be 

 ascertained to a certain extent by various and very simple means. 



The specific gravity of a soil, or the relation of its weight to 

 that of water, may be ascertained by introducing into a phial, 

 which will contain a known quantity of water, equal volumes of 

 water and of soil, and this may be easily done by pouring in 

 water till it is half full, and then adding the soil till the fluid rises 

 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 

 400 grains of water, and gains 200 grains when half filled with 

 water and 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 165 

 grains, its specific gravity would be 1S25, \vater being 1000. 



The presence of clay and sand in any soil may be known two 

 ways ; the first by its tenacity, the other by its roughness to the 

 touch, and by scratching glass when rubbed on it. 



The presence of calcareous matter in soil may be ascertained 

 by simply pouring any acid on it, and observing if it effervesces 

 freely. Calcareous soils are also softer to the touch than any 

 other. 



The presence of organized matter in any soil may be ascertained 

 very satisfactorily by weighing it after being thoroughly dried ; 

 then subjecting it to a red heat, and weighing it again, the weight 

 last found will be the proportion of organic matter. The same 

 object may also be obtained by ascertaining the specific gravity 

 of the soil, but with less accuracy. 



The presence of metallic oxides in a soil may generally be 

 known by their color. Ferrugineous soils, are red or yellow ; 

 cupreous soils, interspersed with greenish streaks, etc. 



