516 EXPERIMENT STATION EECOED. 



tenanee of a Given Difference in Pressure, and On the Energy of Storms, by M. 

 Margules; and The Theory of the Movement of the Air in Stationary Anti- 

 cyclones with Concentric Circular Isobars, by F. Pockels. 



Some relations of meteorology with agriculture, H. Mellish {Quart. Jour. 

 Roy. Met. Sac. [London], 36 (1910), No. loJ/, pp. 77-.0.2 ) .— This article discusses 

 the amount of heat required for the maturing of crops, the relation between 

 wheat yield and the rainfall of the previous autumn, the character of season 

 most favorable to different crops, the topography of fruit lands with special 

 reference to frost, frost protection, i)liysical properties of soils with reference 

 to temperature and absorption of water, phenological observations, relation of 

 forests to rainfall and temperature, and the use of weather forecasts and 

 reports by farmers. The thoroughness and efficiency of the United States 

 weather service are commended. 



The classification of climates on a physiogeographical basis, A. Penck 

 {^itzbrr. K. Pn>usi<. Akad. ir/.s-.s., 1910. XII. pp. 2S.'>-2'i(;) .—In this article the 

 author classifies land climates on the basis of the fate of the precipitation on 

 the land as nival, humid, and arid. These 3 principal classes are further 

 divided on the same basis into 8 climatic provinces as follows: Completely and 

 seminival, polar, subnival, completely and semihumid. and completely and semi- 

 arid. 



Is the air of mountains colder than that of the air at like altitudes? 

 J. Hann (Met. Ztschr.. 21 (1910). Nos. /, pp. 30. 31 ; 5. pp. 215-211; abs. in 

 Beihl. Ann. Phys., S'l (1910), Xo. 12. p. 619). — Observations bearing upon this 

 subject are briefly summarized. 



The action of kainit and carnallite in preventing frost, E. Grohmann 

 (Ftililing's Landw. Ztg., 59 (1910), No. 10, pp. 3-'fl-3J,Ji). — Observations on pots 

 of sand indicated that applications of from 2.5 to 7.5 centner of carnallite and 

 kainit per hectare (111.53 to 334.59 lbs. per acre) refluced the formation of frost 

 to a considerable extent. When, however, the salts were used at rates of from 

 10 to 15 centner per hectare (446.12 to 669.18 lbs. per acre) crusts were formed 

 in the surface soil and the formation of frost was not reduced. 



The effect of the potash salts in reducing frost is attributed to their indirect 

 action in concentrating the moisture in the upper layers of the soil and thus 

 retarding the penetration of the frost. When, however, the salts are applied in 

 such large amounts that soil crusts are formed, frost penetration is not 

 retarded. 



The fight against hail, J. M. Guillon (Rev. Vit., 33 (1910), Nos. 858, p-p- 

 561-568; 859, pp. 589-596. fig. 1; 860. pp. 611-623, fig. 1 ; 861, pp. 6.',5-652. figs. 2).— 

 This article reviews the history of the development of methods of hail protection, 

 as well as the experience of various communities in Europe in employing ex- 

 plosives for the purpose. The author is of the opinion, as a result of his obser- 

 vations, that the results obtained warrant a continuation of further tests of 

 the use of explosives under carefully controlled conditions. 



Meteorology, H. D. Edmiston ( Penn.<<)ilr<ini(i .S7(/. Ritt. 1909. pp. 201-21.'i. 

 3.'f6-361). — The observations here recorded are of the same character as those 

 reported in previous years (E. S. R., 21, p. 213). The summary for 1908 is 

 as follows: 



