84 THE SOIL. 



287. Another most important property, and essential to 

 the fertility of soil, is the power of absorbing moisture from 

 the atmosphere. During the night, soils which possess 

 this property in a sufficient degree arc enabled to con 

 dense a large quantity of water, and thus make up, in a 

 very considerable measure, for the enormous quantity lost 

 by evaporation during the day. 



These powers of absorbing oxygen, of absorbing and 

 retaining moisture, and of forming water, are given to a 

 sandy soil by humus, and also by clay, but far more 

 effectually by the two mixed together. 



288. The richest natural soils are those which contain all 

 these ingredients, sand, clay, lime and humus in due propor 

 tions. Such are the alluvial soils found on the low banks 

 of the Connecticut and many other rivers. These streams, 

 in their course from their sources in the hills, wash against 

 and wear away a great variety of rocks, dissolve and carry 

 along with them portions that have been made soluble by 

 the processes of weathering, and take up quantities of leaf 

 and other vegetable mould, and bring them all away in 

 their current. When, in the winter and spring, they 

 overflow their banks, they deposit all these mingled 

 materials upon the intervale or bottom lands, the low 

 grounds lying between the river and the hills. 



In the lower part of a river s course, these various 

 materials arc deposited in the state of the finest sand or 

 clayey mud ; soils so formed are found to possess an almost 

 inexhaustible fertility. They unite all the materials neces 

 sary for the growth of plants, clay, sand, lime and humus, 

 in circumstances the most favorable, all perfectly mixed, 

 and all reduced to the state of the finest powder. 



289. Next in value to these soils, for permanent culti 

 vation, are the light sandy soils formed by the crumbling 



