METEOROLOGY — WATER. 515 



occurrence of frost, especially during the mouths of September and October, 

 as the nights steadily grow longer and afford greater opportunity for radia- 

 tion, without compensating insolation." Attention is called to the fact that 

 danger from Injury by frost decreases with the approach to maturity and that 

 fully matured fruit can not be damaged except by a severe frost. The fore- 

 caster " should realize that he must carry on this work to a successful conclu- 

 sion from the beginning to the end of the season, or, in other words, that he 

 must ' save the crop.' " 



The ammonia in rain and snow at observation stations of the Charcot 

 expedition, A. Muntz and E. Lain^ {Coinpt. Rend. Aeod. Hci. [Paris], 153 

 {1911), No. 17, pp. 7/i9, 150). — Analyses of 4 samples of rain and 14 of snow 

 collected at different places in the South Polar region showed for rain, a maxi- 

 mum of 9.82 mg. of ammonia per liter, a minimum of 0.25 mg., and a mean of 

 3.12 mg. ; for snow, a maximum of 1.52 mg., a minimum of 0.15 mg., and a mean 

 of 0.42 mg. The maximum for rain is considered abnormal. If this figure is 

 excluded, the mean for rain is 0.S9 mg., which is very close to that observed at 

 Rothamsted, namely, 0.97 mg. Miintz and Aubin found from 0.06 to 0.14 mg. 

 of ammonia in snow and from 0.12 to 0.64 mg. in rain from the Pic du Midi. 

 These results indicate that the distribution of ammonia in rain and snow of 

 the South Polar region is similar to that of Europe. 



Hail insurance in certain countries and its problems (Inst. Internal . Agr. 

 [Rome], Assemble G&n., 3. Sess., Raps, et Etudes Bur. Inst. Econ. et Soc, 2 

 {1911), pp. X+110). — This report deals in some detail with the need of an 

 international understanding with reference to hail insurance, and the organiza- 

 tion of such insurance in different countries, including Germany, Austria, 

 France, Hungary, Italy, and Switzerland ; indicates the general lines on which 

 such insurance should be organized ; and points out the necessity for the sys- 

 tematic collection of further statistics on the frequency and injury caused by 

 hail. It is thought that hail insurance is the most practical, economical, and 

 rational method of dealing, either in part or in whole, with injury caused by 

 hail, that agricultural organizations should encourage it, and states should 

 perfect legislation with this end in view. 



Surface water supply of the Missouri River basin, 1909, W. A. Lamb, 

 W. B. Freeman, and F. F. Henshaw (C7. S. Oeol. Survey, Water-Supply Paper 

 266, pp. 291, pis. 5, fig. 1). — This paper describes the Missouri River basin, 

 and gives results of measurements of flow of streams in the basin, including 

 gage height record, current meter measurements, and daily and monthly dis- 

 charges. 



Analyses of mineral waters, S. D. Averitt and O. M. Shedd {Kentucky 

 Sta. Rpt. 1909, pp. Jfll-'t26). — Partial analyses of miscellaneous samples from 

 different parts of the State are reported. 



Recent methods of sew^age clarification and sludge treatment in Germany, 

 E. KuiCHLiNG (En gin. Neics, 66 {1911), No. 26, pp. 768-770).— This article 

 deals more particularly with the system of sewage purification installed by the 

 city engineer of Elberfeld, Germany, comparing its operation with that of the 

 Imhoff tank system (E. S. R., 24, p. 418). 



In contrast to the Imhoff system shallow tanks are used in the Elberfeld 

 system and the sludge, containing from 71 to 78 per cent of moisture, is removed 

 at frequent intervals. It is stated that some of this wet sludge is used as a 

 fertilizer by farmers, but that better results are obtained with the more 

 thoroughly decomposed sludge obtained by spreading the wet sludge on the 

 surface of the soil where it is allowed to remain until it becomes a compact, 

 earthy mass containing, according to analyses reported, 0.49 per cent of 

 nitrogen. 



