Recent Publications on Manures. 75 



readiest and best of substances, I should think, is the rot heap 

 of weeds and refuse from the garden. It should be kept, as well 

 as other manures, from heavy washing rains, and the full force 

 of the sun ; which may be done at a trifling expense by stobs 

 and boards above, leaving it open to the access of air below ; and 

 turning over with the spade when the heat of decomposition 

 begins to get excessive (about 100°). When heavy rains cannot 

 be thrown off*, the bottom of the heap should rest on a hard 

 surface, to prevent absorption by the soil, and a descent should 

 be made to some reservoir, to collect the liquid manure that 

 flows off. If this were properly attended to, there would be less 

 need for sulphuric acid to fix the ammonia. The soil itself, if 

 in a moderate condition between wet and dry, is capable of 

 absorbing and retaining all the carbonate or ulmate of am- 

 monia needed, as we shall see when treating of Dr. Madden's 

 experiments. Carbonate or ulmate (humate) of ammonia, which- 

 ever of these substances may be formed, is certainly a much 

 better food for plants than sulphate of ammonia : it yields both 

 carbon and ammonia, while much sulphuric acid from the other 

 should be rather prejudicial than otherwise. If the rains are 

 so heavy, and the soil so wet, as to wash out and carry off the 

 ulmate or carbonate of ammonia, it will do the same with the 

 sulphate of ammonia. If the water holding the carbonate or 

 ulmate in solution remains in the soil, it will give it off to the 

 roots of the plant if near, or be absorbed again by the particles 

 of the soil if it is not near, the roots ; evaporation is not likely to 

 take place to the extent anticipated. 



On the subject of nitrates, Mr. Squarey says, " they are 

 found in calcareous strata in the East Indies, South America, 

 France, and Spain, in the valleys of rivers and lagoons, and in 

 the soil. In Spain," he says, " the soil in some places is very full 

 of nitrates, which may be washed out, but are found mixed with 

 common salt. They effloresce from limestone, and may be found 

 on the walls of buildings exposed to the vapour of ammonia, 

 and where Roman' cement is put on. In France the nitrate of 

 potash is formed from animal and vegetable remains, mixed 

 with calcareous matter, as old plaster, chalk, lime, &c, laid up 

 and fermented in beds protected from the weather, and putrid 

 water or urine poured on them. The lixiviation produced from 

 this consists mostly of nitrate of lime, but wood ashes are added 

 to convert it into nitrate of potash, or saltpetre. From every 

 100 lb. of materials, 12 lb. of saltpetre," he says, "are generally 

 got." He quotes Dr. Daubeny for the experiments in which wheat 

 grown with the nitrate of soda gave 23^ per cent of gluten, 

 while that without nitrate had only 19 per cent, to show that 

 the nitrate of soda had been active in producing from its nitrogen 

 more gluten. From the same experiments, it was shown that 



