FAEMERS' INSTITUTES. 229 



these acids we must at the same time provide some neutralizing material with 

 which these acids may combine, i. e., we should seek to form salts with these 

 acids. Lime, magnesia, potash, soda, ammonia may ha used for this purpose, 

 and any of these materials in the soil may serve this purpose and prevent any 

 acid condition. 



EELATIONS TO AMMONIA AND COMBINED NITROGEN. 



These acids of muck are distinguished by a marked avidity for ammonia. 

 So strong is their afldnity for ammonia that it is quite difficult to free them from 

 this base. Even muck in the muck bed is found to contain some ammonia, as 

 I have repeatedly demonstrated. A specimen which I recently examined con- 

 tained 5 pounds of ammonia in the ton of air dry material. And Avhen this 

 material has long been exposed to the air, the amount of ammonia is found to 

 increase. As a class these vegetable acids may be called the ammonia traps of 

 the soil. Ammonia is a valuable manural material because it contains so much 

 combined or active nitrogen. It has become a very important question in high 

 farming how to obtain a sufficient supply of combined or active nitrogen. It 

 is the most valuable and costly element of manures. The agricultural world 

 is now taxing its brains liow to get enough nitrogen in the active forms of 

 ammonia and nitric acid. Ships are sent to the Peruvian Islands to bring 

 guano, Avhich is valuable almost entirely for its ammonia. Other shij^s bring 

 cargoes of nitrate of soda from Chili, Avhich is of value almost entirely for its 

 nitric acid. Earth and sea are ransacked for nitrogen in combined form ; it is 

 the urgent demand of advanced agriculture to-day. Yet the air contains an 

 inexhaustible supply of nitrogen, for nearly four-fifths of air is nitrogen. At 

 every moment it bathes every leaf and stalk of every growing plant, but the 

 plant cannot take a particle of this nitrogen, for it is free or uncombined 

 nitrogen, and it is only when nitrogen is caught and harnessed with hydrogen 

 or oxygen that the plant can make use of this strange substance. The plant 

 may be starving for nitrogen, and this material may be pressed against its very 

 lips, but Tantalus-like it may not drink a particle. The great problem for 

 agriculture to-day is how to catch and harness this wild colt for useful use. The 

 success of agriculture hinges more upon the accumulation and preservation of 

 available nitrogen than upon any other subject. 



The old idea was that the products of decomposition of an organic substance 

 would be rich in nitrogen in exact proportion to the amount of nitrogen in the 

 original substance, provided that none escaped during the process of decompo- 

 sition. You have all noticed partial illustrations of this principle. You all 

 know how much stronger and more heating is the manure when your horses eat 

 plenty of grain, tlian wlien they are fed on hay or straw. You have all noticed 

 the strong odor of hartshorn or ammonia which the grain-formed manure gives 

 off, while no such odor is given off by straw-made manure. It is needless to 

 ask you which kind of manure will give you the best results in your fields. Now 

 it is unquestionably true, as a general rule, that the manure Avill be valuable in 

 proportion to the highly developed character of the food which the animal con- 

 sumes. 



But the mistake has been in assuming that all tlie nitrogen present in any 

 decomposing material is there because it was originally present in the vegetable 

 which is decomposing. A few years ago Deherain of France discovered that 

 when any organic matter entirely free from nitrogen, e. g., sugar, undergoes 

 decomposition under favoral)le circumstances, it combines with nitrogen so that 



