94 Recent Publications on Manures. 



atmosphere may be in action also. If urine is poured on peat, 

 both ulmate and carbonate of ammonia would be formed, and 

 the peat fermented and rendered soluble. Dr. Madden does 

 not say whether ulmate of ammonia is as volatile as the car- 

 bonate of ammonia, it probably is as much, from the feebleness 

 of the acid noticed : if kept moderately cool, however, by turn- 

 ing the heap with the spade, when it approaches 100° (fer- 

 mentation will go on 20° lower), and if kept from washing rains 

 as before observed, a very valuable manure would be produced. 

 In the Gardener s Chronicle lately, as copied from the Bath Chro- 

 nicle, immense effects are stated to have been produced on four 

 successive crops of wheat, from very poor land, by manuring 

 with some prepared manure, of which carbonate of ammonia 

 is the basis, at a cost of 20s. per pound. The editor, following 

 the directions of Liebig, says it would be better converted into 

 a sulphate of ammonia. The great waste, however, of carbonate 

 of ammonia, if kept cool and mixed in composts till buried 

 in the ground, has not been proved ; in the guano, it appears to 

 be long retained, and there is perhaps less waste than is imagined. 

 Carbonate or ulmate of ammonia, producing both carbon and 

 ammonia, must be much more eligible as the food of plants, 

 than sulphuric acid (vitriol) and ammonia. 



From the valuable remarks of Dr. Madden on the necessity 

 of air and moisture, not wetness; the effect of water on heat by 

 its evaporation and radiation, and on electricity by its conducting 

 powers ; but, above all, its effects on the chemical decompo- 

 sition going on in the soil, the stomach of the plant; we see 

 the benefits of keeping it in proper condition by draining, &c. 

 " If the soil is too large-grained and sandy it does not combine 

 properly with the organic matter; a proper proportion of clay, 

 chiefly a hydrate of alumina, he says, in the form of an impal- 

 pable powder, is wanting; but too much of this prevents the 

 the action of the air. The condition of the soil affects vegetation 

 much." If too open by too much sand, evaporation and heat 

 are both at times destructive and excessive. If too much small 

 impalpable powder is in the soil, it gets close and adhesive, and 

 solidifies too quickly, becoming cold and inactive. It is this 

 clay, however, which absorbs and retains moisture and organic 

 substances or their elements, and is indispensable. The benefits 

 of cultivation are, by separating the soil into small pieces, to re- 

 tain fixed air and heat, allowing the heat of the sun to penetrate 

 freely, and retaining it by the nonconducting power of confined 

 air. If left in large coarse pieces, the water evaporates and is 

 carried down rapidly, the gaseous substances escape more, and 

 heat is not confined ; if in small pieces, the organic substances 

 are more intimately mixed, moisture retained, and heat, to in- 

 crease the chemical action. If broken up in damp weather, the 



