14 THE AMERICAN FARMER. 



ent soils. As a rule, they decay quickest in open sandy soils, and last longest in heavy clays 

 or wet peat. It is just so with all organic matters. It is well known that in some grave 

 yards human bodies decay in four or five years, in others only in fifteen or even twenty 

 years. Now, this has an important bearing on the use of manures. In some soils the 

 organic part of the manure disappears quickly, particularly in sandy soils, while in others, 

 particularly loams and clays, they remain much longer, modifying both the chemical compo 

 sition and physical character. 



Again, soluble mineral salts are washed out unequally. As a general rule, those salts 

 which are of most use to plants are held more tenaciously, while those that are injurious 

 wash out easier. 



There is another way in which the composition and constitution is affected by the air 

 that is, through the climate. Alkaline soils and salty soils of various kinds are only found in 

 dry climates. All the saline and alkaline soils of the interior and western parts of our con 

 tinent, and indeed of all countries (except shores) would be soon purified if the rains were 

 abundant enough for numerous springs and streams. The countries are salt and alkaline 

 because these salts have been developed by the disintegration of the rocks, and the soils have 

 not been sufficiently washed out. Even our Connecticut coast salt marshes soon lose their 

 saline character and become fresh if the sea water is excluded.&quot; 



Thus we see that many soils contain in themselves the elements of fertility, which are 

 gradually supplied through the agency of water and air, while others soon become exhausted 

 without the use of manures or other fertilizers to restore the elements that have been extracted 

 by the crops produced. 



Classification of Soils. It is a well known fact that soils frequently, by a gradual 

 process, change from one character to another, so that a minute classification is almost 

 impossible. &quot;We prefer for general reference the arrangement adopted by the noted British 

 authority, Prof. Johnston, which is based upon their chemical constituents. 



&quot; 1st. Pure clay (pipe clay), consisting of about 60 of silica and 40 of alumina and oxide 

 of iron, for the most part chemically combined. It allows no silicious sand to subside when 

 diffused through water, and rarely forms any extent of soil. 



&quot; 2d. Strongest clay soil (tile clay, unctuous clay), consists of pure clay mixed with 5 to 



15 per cent, of a silicious sand, which can be separated from it by boiling and decantation. 



&quot;3d. Clay loam differs from a clay soil, in allowing from 15 to 30 per cent, of fine 

 sand to be separated from it by washing, as above described. By this admixture of sand, its 

 parts are mechanically separated, and hence its free and more friable nature. 



&quot; 4th. A loamy soil deposits from 30 to 60 per cent, of sand by mechanical washing. 



&quot; 5th. A sandy loam leaves from 60 to 90 per cent, of sand, and 



&quot; 6th. A sandy soil contains no more than 10 per cent, of pure clay. 



&quot; The mode of examining with a view of naming soils, as above, is very simple. It is 

 only necessary to spread a weighed quantity of the soil in a thin layer upon writing paper, 

 and to dry it for an hour or two in an oven or upon a hot plate, the heat of which is not 

 sufficient to discolor the paper the loss of weight gives the water it contained. While this 

 is drying, a second weighed portion may be boiled or otherwise thoroughly incorporated 

 with water, and the whole then poured into a vessel, in which the heavy sandy parts are 

 allowed to subside until the fine clay is beginning to settle also. This point must be care 

 fully watched, the liquid then poured off, the sand collected, dried as before upon paper, and 

 again weighed. This weight is the quantity of sand in the known weight of moist soil, 

 which by the previous experiment has been found to contain a certain quantity of water. 



&quot; Thus, suppose two portions, each 200 grs., are weighed, and the one in the oven loses 

 50 grs. of water, and the other leaves 60 grs. of sand, then the 200 grs. of moist are equal 

 to 150 of dry, and this 150 of dry soil contains 60 of sand, or 40 in 100 (40 percent.). It 

 would, therefore, be properly called a loam, or loamy soil. 



