58 Agricultural Irnjilements and I^roduce. 



much ammonia and nitric acid are usually contained in the one, 

 and brought down by the other. The principals in this discus- 

 sion in France are MM, Boussing^ault and Ville ; both of these 

 chemists have made extended series of experiments on plants 

 grown in glass-cases ; their conclusions are, however, diametri- 

 cally opposite, — M. Boussingault contending that plants cannot 

 make use of the atmospheric nitrogen, but must be indebted to 

 the nitric acid and ammonia in the air for their supply in excess 

 over that furnished by the soil ; M. Ville maintaining that, in 

 the absence of both of these, an increase of nitrogen in plants 

 still takes place. A Commission of the French Academy of 

 Sciences, recently appointed to look into this matter, leans rather 

 in its report to the side of M, Ville, but the question is still far 

 from being set at rest. 



M. Barral has determined the quantity of ammonia and nitric 

 acid brought down by rain in Paris. M. Boussingault has re- 

 peated these experiments as regards ammonia in Alsace, and 

 finds the quantity very much smaller than in the rain of the 

 city, a circumstance which we should be prepared to expect. 

 M. Boussingault has also examined, with the same object, the 

 water of fogs and dew, and of rivers and streams. M. Ville has 

 cai'efully determined the ammonia existing in the air both in the 

 interior and suburbs of Paris. 



Mr. Lawes and Dr. Gilbert have published the results of an 

 inquiry into the quantity of ammonia and nitric acid in rain 

 falling at Rothamsted, in Hertfordshire. The methods of deter- 

 mining small quantities of nitric acid are at present so imperfect, 

 that Messrs. Lawes and Gilbert have not thought it well to pub- 

 lish their results as to this substance, but they are led to believe 

 that in quantity it exceeds that of ammonia in rain. Besides the 

 names Ave have mentioned in connection with these researches, 

 other continental and English chemists might be referred to, if 

 circumstances admitted of greater amplification. It is, however-, 

 dbvious, that in this hurried sketch we have omitted all notice of 

 many investigations on this and other subjects of agricultural 

 chemistry which might well claim attention in a more extended 

 review. 



Finally, we must not omit to mention, tliat the trade in artifi- 

 cial manures, which is rapidly rising into such national import- 

 ance, especially in England, is receiving the most important aid 

 at the hands of chemical science. Not only are the various 

 waste substances of manufactures and of daily life worked up 

 into available form, but the manures produced by chemical 

 means, more especially the superphosphate of lime, are daily 

 improving in charactei", mainly through the suggestions of 

 chemists who have specially devoted themselves to this branch of 



