MANURE. 157 



Nitrogen gives salts power to do more work in the same 

 time. It is a labor-saving machine, enabling the farmer from 

 the same gromid, and with the sam.e time and labor, to reap 

 larger rewards. Natural vegetation is a low-pressure engine, 

 but it will bear any amount of pressure, so beautifully built 

 is it in all its parts. Inorganic salts are the water, geine the 

 fire which raises the steam to drive this machine, filling the 

 thousand cylinders which are distributed throughout plants. 

 Nitrogen is the regulator of this engine. Nature has every- 

 where put her machine into the hands of man. She keeps it 

 in working order, by her gentle steam. She takes man as 

 her apprentice, and her generous hand supplied the daily 

 bread while man was learning the construction of the valves, 

 the working of pistons, the real power of the engine, the 

 source of the steam. These, even though dimly seen, nature 

 demands should be worked up to full pressure, when the 

 apprentice sets up for himself, and is determined that the 

 sweat of his brow, while it feeds his body, shall also purify, 

 enlarge and strengthen his intellect. 



In making agricultural trials with pure ammoniacal salts 

 (166), in which the nitrogen exists as ammonia, or as an 

 acid united with ammonia, and with nitrates, in which the 

 nitrogen exists as an acid, it is to be remembered that the 

 base with which this nitrogen acid is combined, acts an im- 

 portant part. The influence of the base is to be deducted 

 from that rightly due to the nitrogen, as determined by 

 experiments. What then is the influence of pure salts of 

 ammonia 1 It has been proved, again and again, especially 

 by Jacquemart, in France, and by Kuhlmann, in Flanders, 

 that pure salts of ammonia act like ordinary nitrogenous 

 manures. Their -energy of action, their relative value, is 

 almost in direct ratio to their nitrogen. 



This is a doctrine, which, limited by the circumstances 



• ^', 



