We see, then, that while nitrification proceeded more energetically 

 in the natural soil with each increase in the amount of water added, up 

 to 25 per 100, this was not the case when farmyard manure, equivalent 

 to 20 tons per acre was present. In the case of the manured soil, much 

 the best result was obtained with 15 of water per 100 of soil. With 20 

 of water per 100 of soil there was no benefit from the addition of the 

 manure ; and when the water reached 25 per cent, the soil contained 

 much less nitric acid than if no farmyard manure had been applied ; 

 denitrification had clearly been active in this case. Deberain's results 

 were not free from irregularities, and deserve careful repetition ; they 

 are, however, quite consistent with the general ideas as to the most suit- 

 able conditions for the nitrification ot organic matter furnished by the 

 prolonged experience gained in France as to the most profitable way of 

 managing artificial nitre beds, which in that country were kept under 

 cover. These beds consisted of heaps of organic matter undergoing 

 nitrification. The proportion ot water present was found to be of great 

 importance. As nitrification advanced this proportion was carefully 

 diminished. If this precaution was neglected very little nitre was 

 finally obtained. We should judge, therefore, that moderately dry soils 

 are those most likely to yield a profitable return with farmyard manure t 



The immense difference between the manurial value of the solid and 

 liquid excrements of animals is shown in a striking manner in the Ger- 

 man experiments; and the analysis of the dung, and of the farmyard 

 manure which they employed, showed that there effect on crops was 

 plainly connected with the proportion of soluble and active nitrogenous 

 matter which they contained. The original voidings of the animal have 

 a far greater manurial value than the final product of the manure heap 

 which the farmer carries to his fields. In the whole progress from the 

 stables to the field the loss of nitrogen is going on, this loss falling on 

 the most valuable constituent of the manure, and resulting finally in a 

 residue of comparatively inert matter (i). Maercker estimates the loss 

 of nitrogen in the ordinary preparation of farmyard manure as equal to 

 45 lb. per beast in one year. One practical conclusion from these state- 

 ments is the economy of feeding animals on the land whenever prac- 

 ticable. The whole subject of the economic preparation and preserva- 

 tion of farmyard manure is being actively investigated in Germany. 



K. W A KINGTON, 



Harpenden, Herts. 



(1) It is unfortunate that the Germans use the term " albumiuoid nitro- 

 gen" for all forms of insoluble nitrogenous matter, and thus favour the idea 

 that albuminoid nitrogen has but little manurial value. One has only to re- 

 member that the whole of the nitrogen in dried blood, fish manure, powdered 

 horn, and oil-cakes is in this condition to see the falsity of such a notion. The 

 albuminoids of fresh dung (chiefly nuclein) are specially insoluble, as they 

 have resisted the process of digestion. The insoluble nitrogenous matter of 

 humified manure cannot with any propreity be called albuminoid ; it falls in 

 the same analytical class as albuminoids simply by virtue of its insolubility. 



