8 fiENERAl. PROPERTIES OK LIME. 



Carbonate of lime, if obtained from pulverized limestone, would have nearly the same 

 mechanical effect in soil as sand. It has but little affinity for water ; and hence so far as 

 it exerts any mechanical agency, it operates like sand. In the soils of New-York, and 

 more especially in those of the New-England States, the quantity of carbonate of lime is 

 so small, that it has no perceptible mechanical influence. But there is another form of car- 

 bonate of lime, which exerts a decided influence : this is marl, a carbonate of lime, which 

 is in a state of fine subdivision, and is combined with 4 or 5 to 10 per centum of organic 

 matter. This substance, which is esteemed highly as a fertilizer, is a powerful retainer of 

 water : it even ranks higher than alumina. It truly deserves the reputation it has acquired 

 as a fertilizer, though we doubt whether its real action in the soil has been understood. 



Carbonate of lime, then, in the form we should obtain it by grinding rocks of limestone, 

 would oj>erate only mechanically like fine sand, by giving more porosity to the soil. In 

 the form of marl, however, it gives tenacity to soil, by increasing its retentiveness. 



Carbonate of lime, as a salt of the earth, owes its importance to the relations it sustains 

 with organized bodies, as is shown by their analyses. It is almost always an element, and 

 a most essential one, of the animal tissues. Thus in the lower orders of the animal king- 

 dom, lime is necessary to form the shell, covering or habitation of the species; in the 

 higher, the bones are composed of salts of lime, all of which are derived from the soil. So 

 in the vegetable kingdom, salts of lime are abundant in the ashes of all kinds of woods, and 

 especially so in that of bark. We may therefore regard this element as one of the most, 

 important, and one which must be present in all good soils. 



Carbonate of lime is insoluble in pure water, but the farmer is under no necessity to 

 provide the means for its solution. Rain water carries down to the earth carbonic acid, 

 the presence of which enables water to dissolve it. So probably the development of car- 

 bonic acid in the soil itself may aid in giving solubility to carbonate of lime. I need not, 

 however, dwell upon this subject, as, under carbonic acid and the organic matters of the 

 soil, I shall have occasion to call the attention of the reader again to it. 



The salts of lime, found in soils, are the phosphate, crenate, apocrenate, carbonate, and 

 perhaps the humate and silicate. In weak acids, lime is quite soluble, but they form salts 

 with different degrees of solubility in water. These salts are never in excess in any of 

 the New-York soils : indeed they are really deficient, and, in good husbandry, have to be 

 added in forms which are considered as a manure. In fact, one of the great efforts of the 

 farmer is to supply lime in sufficient quantity to meet the wants of his crops. 



Few subjects have enlisted the attention of agriculturists, so much as the use and effect 

 of lime in and upon soils. The facts very generally go to prove its great value : its action, 

 however, has not been so generally understood. A subject which involves many intricate 

 questions can scarcely be expected to obtain for itself an uniform opinion, or a theory which 

 all will readily adopt. Analysis proves the constant presence of lime in vegetables : hence 

 there is no doubt that it should be present in all soils, to supply the wants of vegetation. 

 But its use and functions do not terminate in supplying a material for nutriment : there 

 are certain reactions of lime upon other elements in the soil, which equal in utility the one 



