114 DRAININGS. 



posed of nitrogen and oxygen, ammonia of nitrogen 

 and hydrogen ; the difference just spoken of, as oc- 

 curring in putrefactive fermentation when the manure 

 is mixed with the powerfully alkaline lime, consists 

 simply in the circumstance that the nitrogen unites, 

 not as in ordinary putrefaction (without lime) with 

 hydrogen, but with oxygen, which is found in the air, 

 in water, in all plants, and, iti short, everywhere in 

 nature. The same proceeding is adopted in the 

 manufacture of saltpetre ; only, in addition to lime, 

 wood-ashes are also employed, because here nitrate 

 of potash is sought to be obtained. 



In many places it is a prevalent custom to throw 

 a few bushels of quicklime into the empty reser- 

 voirs in which drainings accumulate, in order that 

 the urine, as it flows into the receptacle, may always 

 find lime. From the theoretical considerations just 

 brought forward, it is not improbable that by this 

 mode of treatment the manuring constituents of 

 drainings are equally well preserved, since the nitrate 

 of lime is not volatile, and is, we may conjecture, as 

 efficacious a manure as the salts of ammonia. To 

 be able, however, to speak with full certainty upon 

 this point, more chemical examinations of the alter- 

 ations thus effected, and further practical trials of the 

 fertilizing power of these drainings, when compared 

 with ordinary drainings on the one hand, and with 

 those treated with sulphuric acid on the other, must 

 be instituted. Experiments which 1 have already 

 made, and which will be hereafter continued, have 



