260 GUANO. 



lime in the soil, is at once converted into neutral 

 phosphate of lime, which requires to meet with another 

 solvent at the place of formation to effect its diffusion 

 through the soil, whilst phosphate of ammonia spreads 

 through a lime soil just as if there was no carbonate of 

 hme in it. The phosphate of ammonia formed when 

 guano is moistened with water (PO5 + 3]SrH40), loses in the 

 air one-third of the ammonia. It is owing to this circum- 

 stance that guano, Avhen quite dry, will keep without 

 alteration ; whereas, when it has been fraudulently moist- 

 ened, to increase the weight, it loses, by keeping, con- 

 siderably in ammonia. 



If guano, just before its application on the field, is 

 moistened with water and a little sul]3huric acid, suffi- 

 cient to give the water a slightly acid reaction, the decom- 

 position now mentioned, which otherwise requires days 

 and weeks, is effected in a few hours. 



That guano should not produce much effect in very 

 dry weather needs no explanation, because, without 

 water, no substance will act in the ground ; that it 

 should, however, equally fail in very wet weather, is, 

 undoubtedly, owing in part to the fact that the oxalic 

 acid is washed out, as an ammoniacal salt, by the rain 

 water, and that there is, accordingly, a corresponding quan- 

 tity of phosphoric acid not made soluble. By the above 

 simple and cheap means the injurious influence of wet 

 weather upon guano may be completely guarded against, 

 inasmuch as the water and sulphuric acid ensure the con- 

 version into a soluble form of the whole of the phos- 

 phoric acid, which could have been brought into that 

 condition by the oxalic acid. 



The rapidity with which a nutritive substance employed 

 in the shape of manure produces an effect, depends 

 essentially upon the speed with which it spreads through 

 the soil, and this, again, upon its solubility ; hence it is 



