204 CAUSES OF WASTE CONSIDERED. 



acids of soil, of vegetable origin, which, chemists have recently 

 ascertained, the humic acid is by far the most frequent, abundant, 

 and important of all. Of course when lime is applied to an acid 

 soil (i. e., any one needing the chemical action of calcareous earth), 

 thfc most abundant resulting salt will be the humate of lime, which 

 being insoluble in water (or very nearly so), is entirely secured 

 from the waste to which a soluble salt might possibly be, but is 

 not necessarily liable. 



4. "The ultimate resolution of all vegetable matter in the soil" 

 continues Professor Johnston, " into carbonic acid and water, like- 

 wise aids the removal of the lime. For if the soil be everywhere 

 impregnated with carbonic acid, the rain and spring waters that 

 flow through it will also become charged with this gas, and thus be 

 enabled to dissolve so much the larger portion of carbonate of lime. 

 Thus, theory indicates, what I believe experience confirms, that a 

 given quantity of lime will disappear the sooner from a field, the 

 more abundant the animal and vegetable matter it contains." (p. 

 399, 400.) Answer. First, to the last incidental passage, I will 

 merely state unqualified dissent. So far from the quantity of vege- 

 table matter promoting the escape of the lime, it would tend to 

 prevent such waste, if otherwise likely to occur. According to 

 my theory of the action, the lime and vegetable matter in soils 

 combine with each other, and with other parts of the soil, each one 

 thus serving to retain the others, if otherwise liable to waste. 



Whatever may occur in old manure heaps, or in the chemist's 

 laboratory, it is not likely that much, if any, vegetable matter in 

 soil (and when not in great excess), can pass through all the va- 

 rious stages of decomposition, to the last, that of being resolved into 

 carbonic acid and water. Previous changes would slowly render 

 the parts soluble, and fit to be drawn up by the roots of plants ; 

 and probably all would be so used, so that very little reaches the 

 gaseous state. But if carbonic acid should be formed, the pro- 

 duction would be very slow, so that the results would be all required 

 for, and taken up, by plants in aid of their support and growth, 

 almost as fast as they were produced. Thus, there would be but 

 little if any opportunity for the alleged waste of lime^ in conse- 

 quence of the organic matters in the soil reaching the last stage 

 of decomposition, and being reduced to carbonic acid and water. 



So far, the sundry particular reasons offered in support of the 

 alleged transitory operation and existence of lime in soils have been 

 opposed by particular objections. But still stronger grounds of 

 objection may be assumed in general views, which will now bo 

 brought forward. 



to place in the same class both carbonate and phosphate of lime entirely ; 

 and also caustic lime, for much the greater part of the bulk of an ordinary 

 application as manure. 



