INFLUENCE OP NITRIC ACID. 



307 



that place is about the same latitude as Rio de Janeiro. These deter- 

 minations seem to show that much more nitric acid falls in the tropics 

 "than in temperate regions. This may readily be seen by making a com- 

 parison of the following statements of determinations made in several 

 localities : 



Determinations of Nitric Acid (HNOs) in Rainfall. 



Station. 



Nitric acid (milligrams 

 per liter of rain-water). 



Authorities. 



Caracas, Venezuela 



2.23 (mean) 



Muntz and Marcano (1). 



Saint Denis, Bourbon island. . . 



2.67 (mean) 



Muntz and Marcano (1/). 

 Homans (1^0- 



Sourabois, Java 



2.3-2.87 



Lincoln, New Zealand 



0.578 



G. Gray (2). 

 Kellner (2). 

 Muntz and Aubm (3). 



Tokio, Japan .... 



Pic du Midi, Pyrenees 



0.327 



trace only 



Eothamsted, England 



Manhattan, Kansas 



.670, mean for 1 year . . 

 .702, mean for 3 years. . 



.180 



R. Warington (4). 

 Failyer, Willard and 



Breese (5). 

 Boussingault (6). 



Liebfrauenberg, Alsace 





The determinations of nitric acid in rain-water, both in temperate and 

 tropical regions, show that the amount is not constant, and the figures 

 given in the above table must be looked upon as means that fluctuate 

 greatly. At Caracas, for example, a maximum of 16.25 was reached on 

 one occasion and on another a minimum of 0.20 milligrams to the liter. 

 The amount doubtless varies with the electrical discharges, as Muntz and 

 Marcano state.* 



(1) Comptes Rendus, 108, pp. 1062-1064; elevation of Caracas station, 922 meters. 

 (1') Comptes Rendus, 108, p. 1062; 19 observations; maximum, 12.5; minimum, 0.4. 

 (I'O Annales Agronomiques, Paris, x, 1884, pp. 83, 84. 



(2) Quoted from Warington. Jour. Chem. Soc, vol. Iv, 1889, p. 543. 



(3) Sur la nitrification atmospherique. Muntz et Aubin. Comptes Rendus, 95, 1882, pp. 919-921, 

 In 6 rains, 3 fogs, and 4 snows they found " almost a complete absence of nitrates." 



(4) The Amount of Nitric Acid in the Rainwater at Rothamsted. R. Warington. Jour. Chem. 

 Soc, vol. Iv, 1889; Transactions, pp. 537-542. Warington's mean for the year is given as 0.139, but 

 his figures add up 0.149. I have used the latter. I have regarded the nitrogen as nitrates, for, as 

 Warington says, the amount of nitrous acid is " extremely small and only to be appreciated by the 

 delicate napthylamine test." 



For other determinations see Annales Agronomiques, 1881, vii, pp. 429-456; also On the amount 

 and composition of the rain and drainage waters collected at Rothamsted. Lawes, Gilbert and 

 Warington. Jour. Roy. Agr. Soc. of England, 2d ser., vol. xvii, 1881, pp. 241-279; pp. 311-350. On 

 page 268 the nitrogen is given for 9 other stations. See also Recherches sur I'existence et le role 

 de I'acide nitreux dans le sol arable. Ch. Chabrier. Annales de Chimie et de Physique, 4me ser., 

 1871, xxiii, pp. 161-193. 



(5) Ammonia and nitric acid in atmospheric waters. Second Annual Report Experiment Station 

 Kansas Agricultural College for 1889. Topeka, 1890, pp. 123-132; Trans. Kansas Acad. Sci., vol. xii, 

 1889-'90, pp. 21-24. 



(6) Quoted from Muntz and Marcano. Comptes Rendus, 108, p. 1063. 

 * Comptes Rendus, 108, p. 1062. 



