308 AMMONIA AND NITRIC ACID. 



We had reason enough to believe in a partial resto- 

 ration to the soil of nitrogenous food by air and rain, 

 bat that it should be augmented was quite unexplained ; 

 because this presupposed that ammonia and nitric acid 

 were produced from the nitrogen of the atmosphere, in 

 evidence of which we had no facts whatever Very 

 recently this source of the increase of the nitrogenous 

 food of plants was discovered by Schonbein, and the 

 problem was solved in the most unexpected manner. 



In his experiments upon oxygen, Schonbein found 

 that the white fume emitted by a piece of moist phos- 

 phorus is not, as was previously believed, phosphoric 

 acid, but nitrate of^ ammonia. 1 myself had an oppor- 

 tunity of seeing this proved at a lecture, illustrated by 

 experiments, which Schonbein delivered at Munich in 

 the summer of 1860. It is probable, as he states, that 

 in this reaction the nitrogen of the atmosphere, by a 

 kind of induction, 'combines with three equivalents 

 of water, whereby on the one hand nitrous acid, and 

 on the other ammonia, are formed ; just as is well 

 known that under the influence of a higher tempera- 

 ture, nitrite of ammonia is decomposed into w r ater and 

 nitrogen gas. The most striking fact is, this salt is 

 formed under circumstances which we should have been 

 led to suppose were precisely those opposed to its for- 

 mation ; but the production of the peroxide of hydrogen 

 (so easily decomposed by heat), during the slow oxida- 

 tion of sether, which is attended by a perceptible evolu- 

 tion of heat, is a fact not less certain, and hitherto 

 equally unexplained. 



The formation of nitrite of ammonia during this slow 

 process of oxidation made it probable that it takes place 

 everywhere on the earth's surface where oxygen enters 



1862, for the Agric. Union in Saxony, the following crops per acre were 

 obtained in 1861 : 



Wheat. 



Corn. Straw. 



3 cwt. Jarvis guano produced 2244 Ibs. 4273 Ibs. 



3 " Baker " " 2929 " 5022 " 



6 " steamed bones " 3015 " 4755 



Unmanured " 1955 " 3702 " 



