234 ANNUAL OF SCIENTIFIC DISCOVERY. 



AMMONIA IN THE AIR. 



AT the meeting of the American Association at New Haven, Pro- 

 fessor Horsford presented a paper in continuation of the communica- 

 tion made by him to the Association in 1849,* in relation to the 

 ammonia in the atmosphere. The relative quantities of ammonia 

 found in the rain and snow water had been determined in a number 

 of instances. The following table exhibits the results of several de- 

 terminations and their date : 



Ammonia in Rain and Melted Snow in one Cubic Metre. 



1849, Dec. 22, in rain, 1.56 gr. 

 " " 29, in snow, 2.63 " 



1850, April 4, in rain, 0.24" 

 " " " in snow, 0.72" 

 " March 18, in " 1.49 " 

 " " 22,23, in " 0.96" 

 " July 16, in rain, 1.29 " 



Professor Horsford announced his intention of continuing his obser- 

 vations throughout the coming year, that all the sources of error 

 might be eliminated, and the subject fully investigated. 



Origin of Ammonia in the Atmosphere. At the American Asso- 

 ciation, New Haven, a paper was presented from Dr. A. A. Hayes, 

 on the assumed existence of ammonia in the general atmosphere. 

 The object of this paper was to show that ammonia is not found to be 

 a general constituent of the atmosphere, but that the ammonia found 

 by chemical analysis of the air near the surface of the earth is derived 

 from an organic substance discovered by Zimmerman, and called by 

 him pyrrhine. To this substance, which exists universally in rain 

 and snow water, Dr. Hayes attributes the fertilizing effects of snow, 

 rain, and the water contained in arable soils. He adduced instances 

 of very rapid vegetation as produced by the formation of pyrrhine in 

 fermenting mould. He regards ammonia as a poison to plants, though 

 he attaches great value to it as a neutralizing agent to acids of soils 

 and as serving to convey other ingredients, such as carbonic acid and 

 the organic acids of soils, into the circulation of plants. 



CARBONIC ACID IN THE AIR. 



M. LEVY, a chemist who has been engaged for several years in 

 investigations upon atmospheric air, reports to the Academy of Scien- 

 ces the result of his labors. His communication is addressed to the 

 Academy from South America, and signalizes facts which are highly 

 paradoxical, especially in relation to the quantity of carbonic acid 

 which the air contains. He finds in the months of August and Sep- 

 tember forty-seven parts of this acid in one thousand parts of air, 

 while in the months of March, April, May, June, and July, the quan 

 tity of this acid never exceeds three or four parts in ten thousand. 

 He affirms that he has been very exact in his experiments, and made 



* See Annual of Scientific Discovery, 1850, p. 219. 



