32 TALKS ON MANURES. 



other manure was found to contain, in whatever form, 7 per cent 

 of nitrogen, the chemist reported that he found in it 8 per cent 

 of ' potential ' ammonia. Dried blood contains no ammonia, but 

 if it contained 14 per cent of nitrogen, the chemist would be justi- 

 fied in saying it contained 17 per cent of potential ammonia, from 

 the fact that the dried blood, by fermentation, is capable of yield- 

 ing this amount of ammonia. We say a ton of common horse- 

 manure contains 10 or 12 Ibs. of potential ammonia. If perfectly 

 fresh, it may not contain a particle of ammonia ; but it contains 

 nitrogen enough to produce, by fermentation, 10 or 12 Ibs. of am- 

 monia. And when it is said that dry swamp-muck contains, on 

 the average, 2.07 per cent of potential ammonia, it simply means 

 that it contains nitrogen enough to produce this amount of am- 

 monia. In point of fact, I suppose muck, when dug fresh from 

 the swamp, contains no ammonia. Ammonia is quite soluble in 

 water, and if there was any ammonia in the swamp-muck, it 

 would soon be washed out. The nitrogen, or ' potential ammonia,' 

 in the muck exists in an inert, insoluble form, and before the 

 muck will yield up this nitrogen to plants, it is necessary, in some 

 way, to ferment or decompose it. But this is a point we will 

 discuss at a future meeting." 



CHAPTEK VII. 

 TILLAGE IS MANURE. 



The Doctor has been invited to deliver a lecture on manure 

 before our local Farmers' Club. " The etymological meaning of 

 the word manure," he said, " is hand labor, from main, hand, and 

 ouvrer, to work. To manure the land originally meant to culti- 

 vate it, to hoe, to dig, to plow, to harrow, or stir it in any way so 

 as to expose its particles to the oxygen of the atmosphere, and 

 thus render its latent elements assimilable by plants. 



" When our first parent," he continued, " was sent forth from 

 the Garden of Eden to till the ground from whence he was taken, 

 he probably did not know that the means necessary to kill the 

 thorns and thistles enhanced the productiveness of the soil, yet 

 such was undoubtedly the case. 



