POWERS OF SOILS. 353 



sorbing and retaining water, hy the amount of i)ealy matter wliicli it contains, subject to 

 modification by its fineness. 



Tiiat it is the vegetable or organic matter coiuained and intimately combined in soils 

 which give them in the main their powers, is supported by the fact, that when it is 

 destroyed or removed by ignition, very little difl'erence exists among them as it regards the 

 powers in (|UPstion. This statement is confirmed when experiments arc made upon marl 

 and clay first in their natural slate, and afterwards when ignited. In the condition to 

 which they are brougiil by this process, they differ Init a trifle from each other, as it re- 

 gards the amount of moistine thejMvill absorb in equal times and under similar conditions. 

 It seems, that after burning, the different kinds of soils are brought down to the same 

 standard. Thus, in fifteen samples of soils selected from different districts, some of which 

 were clay and sand, together with peat and marl, on being ignited, they absorbed nearly 

 equal quantities of moisture in equal times : they at most differed only between one and 

 two grains in the amount of water which they absorbed. Two hundred grains of soil were 

 selected for these experiments : they were first moistened with water, till perfectly imbued 

 with it, and, in four hours, they were weighed. This operation was repealed at equal 

 intervals, for manj^ times in succession, and always with the same results ; the peat, or 

 nearly pure vegetable matter, scarcely losing any water in the course of a few hours, 

 while sand would lose almost all its water, and become nearly dry. After they were 

 ignited, however, the_v dried sensibly at the same rate ; or when left to absorb moisture 

 after undergoing this process, the sand absorbed nearly as much water as the marl or clay, 

 or the common soils which had been burnt. 



From the foregoing statements, it is evident that soils ought not to be subjected to the 

 process of paring and burning, without special reasons. If there is no objection to burning, 

 on the score of the loss of organic matter, together with a loss in its power of absorbing 

 moisture, then the process will be followed with advantageous results ; for it is unques- 

 tionably true that the mineral or organic matter is more soluble in consetiuence of having 

 been ignited. Sandy soils, and all the varieties of loams, are rarely improved b\' burning. 

 When all the vegetable matter is burned ofi", they must necessarily be injured. So, on 

 the other hand, the addition of finely divided vegetable matters, if it served no other pur- 

 pose in soils than to aid and assist in the absorption and retention of moisture, this purpose 

 itself would be quite an important one, and worthy of being secured. Water, in due 

 proportion, must always be regarded as one of the essential elements of a good soil : it is, 

 as it were, the moving power. In this light it would be regarded, if if was merely the 

 medium for transmitting nutriment through the body of the vegetable ; but it is imj)ortant 

 in other respects, and hence growing plants must have a supply, or else they will suffer 

 or die, according to the degree in which they are deprived of this element. 



[Agricblt0ral Report.] , 45 



