CHEMICAL SCIENCE. 271 



and acetic acid is formed. The heat produced by the combination of oxygen 

 with the hydrogen of alcoholic vapor is not a new quantity gained from a 

 special food for respiration, but it is heat from one source substituted for the 

 heat which would have been obtained from another source. 



Alcohol, in changing into aldehyde, abstracts oxygen from the system. 

 The result of this is an increased respiration to restore the oxygen thus taken 

 away, and an apparent increase of heat. The action of alcohol in the system, 

 so long as it remains alcohol, is to excite and stimulate ; afterward, as alde- 

 hyde, it acts as an anaesthetic. 



AiOIOXIA AND XITEIC ACID IX RAIX-WATEK. 



The following are the results of the experiments undertaken by Messrs. 

 Lawes and Gilbert, of England, for the determination of the amount of ammonia 

 and nitric acid present in rain-water. The average of the determinations 

 made on monthly mixed samples of rain which fell at Rothamsted, England, 

 during more than a year, gave about one part of ammonia per million of rain- 

 water : the average of many determinations by Boussingault at Alsace, hi 

 France, was about four fifths of this amount ; while the estimations of M. 

 Betnal and Boussingault at Paris gave as much as 3 or 4 parts, or even more, 

 of ammonia per million of rain-water. The amounts of ammonia obtained by 

 Messrs. Lawes and Gilbert hi the rain of different entire months, when con- 

 sidered in connection with the registered amounts of fall, the direction of the 

 wind, and the general characters of the weather, were perfectly consistent in 

 kind with the results of Boussingault in his special examinations of ram falling 

 under different circumstances, of the water of dew, fogs, etc. 



In regard to the quantities of nitric acid obtained, the authors do not speak 

 with as much confidence concerning the ammonia, as the methods of de- 

 termining small quantities of nitric acid are by no means satisfactory. As a 

 general result, however, it would seem that while the per centage amount of 

 ammonia was generally less in the rain of thunder-storms and when there was 

 a large fall of rain, the amount of nitric acid, on the other hand, appeared to 

 be increased under the influence of storms. The results further indicated 

 that the amount of nitrogen yielded by rain-water hi the form of nitric acid, 

 was considerably greater than that which existed as ammonia ; and since thera 

 could be no doubt that nitrates applied as manure greatly enhanced the growth 

 of plants by virtue of the nitrogen they contained, the amount of nitrogen 

 brought down from the atmosphere in the form of nitric acid must be con- 

 sidered to have a very important influence on vegetation. Chemical Gazette. 



INVESTIGATIONS IX AGRICULTURAL CHEMISTRY. 



The following communication has been read before the French Academy, 

 by M. Roy: 



Of all the ammoniacal salts, the carbonate of ammonia is the only one which 

 furnishes assimilable nitrogen on a large scale. The leguminous plants of 

 artificial soils have the remarkable faculty of absorbing gaseous carbonate of 



