METEOROLOGY— WATER. 533 



. velocity of the wind was from 1 to 5 meters per second, although the heaviest dew 

 was observed when tin- velocity of the wind was from 5 to 6 meters per second. The 

 average chlorin content of the precipitation was L7.9 mg. per liter, of ammonia 0.9 

 mg. per liter, nitric acid 0.8 mg. per liter. 



The contenl of nitric acid as well as ammonia declined as the length of the rainy 

 period increased. Thunderstorms exerted no influence on the composition of the 

 precipitation. The ammonia contenl was higher after periods of drought. Precipi- 

 tation which occurred during a sea wind contained tin- smallest amounts of ammonia 

 and nitric acid; thai which occurred during a wind from the direction of the town 

 contained the largest amounts. The highest ammonia content was observed with a 

 wind velocity of 46 meters per second; the maximum nitric acid content with a 



velocity of '■'> to 5 meters per second. 



I»e\\. frost, etc., contained nearly L'.l times as much ammonia, a correspondingly 

 smaller amount of nitric acid, and a relatively Jarger amount of chlorin than rain. 

 snow, etc. 'Id icy also almost always contained some nitrons acid. The variation- in 

 the ammonia content of dew, frost, etc.. depending upon the direction of the wind, 

 were similar in character to those observed in case of rain. snow. etc. and as in tin- 

 case of the latter, the composition of the dew , frost, etc.. was n< it affected by thunder- 

 Storms. An increase in the velocity of the wind during precipitation resulted in a 

 lowering of the ammonia content. 



It is estimated that during the whole period of observation the precipitation carried 

 down to the soil L.22 lbs. of combined nitrogen per acre. The precipitation richest 

 in nitrogen occurred during the wannest months, July and August. 



The amounts of nitrogen as ammonia and as nitric acid, and of chlorin 

 in the rainwater collected at Rothamsted, N. II. J. Mii.i.kk {Jour. Agr. Sci., / 

 ( luor, . No. •-'. /'/-. 280 SOS). — This is a detailed summary and discussion of data relat- 

 ing to this subject, which have heen more briefly reported elsewhere I E. S. h.. 16, 

 p. 856). In addition to the full tabulated data, a bibliography of 125 references to 

 Literature relating to the composition of atmospheric precipitations is given. 



Nitrous acid in sea water, E. Bodtkeb | ( 'hem. Ztg. } 29 1 1905 I, No. 73, p. 

 Determinations by means of the batterer iodin-zinc-starch solution or ( rreiss's reagent 

 Bhowed 0.002 to 0.01 nig. of nitrous acid | Nj0 3 ) per liter of sea water taken at Drobak 

 Biological Station on Christiania Fiord. This is about as much as the author found 

 in rain water and makes it questionable whether nitrous acid generally plays any 

 part in the nitrogen absorption of sea plants. 



Neolithic dew ponds and cattle ways, A. J. and (i. Hibbakd {New York: l>. 

 Van Nostrand Co., 1905, pp. XII 70, figs. 25). — This hook is interesting as showing 

 how a primitive people solved the problem of securing a water supply in their hill 

 settlements where springs and streams were not available. The thermodynamics of 

 the dew ponds, which condensed and collected the moisture of the air, is explained. 



Recent progress in matters of water supply and sewage disposal, <J. \V. 

 Fuller {Jour. Amer. Med. Assoc., 45 {1905), No. 15, />/<. 1059-1065). — A paperread in 

 the section on hygiene and sanitary science of the American Medical Association, at 

 the fifty-sixth annual session, July. 1905, discussing the use of copper sulphate for 

 purification of water supplies and reviewing progress in purification of water by sed- 

 imentation, filtration, etc., in water-supply control, and in disposal of sewage (by 

 dilution, filtration, ami septic treatment). The sewage pollution of oyster- and 

 other shellfish is also referred to. 



A contribution to the study of the purification of waste waters of towns 

 and of industries, A. Calmettb, E. Boullangeb, and E. Roi ints (.!/</<. last. Pas- 

 teur, 19 {1905), No. //, /r . 529-540). — The methods used and results obtained in a 



series of studies of the rate of destruction of the organic impurities of sewage hy 

 anaerobic fermentation in septic tanks are repotted. 



