watp:r — SOILS. 427 



434, Ji<J- i) ■ — A cliiirl is tJciviMi which shows the rainfall for each lunar i)hase during 

 the whole year an<l the .summer months, April-Heptember, compiled from observa- 

 tions during '24 years at (Jreenwich. The curves "agree in j)resentiMg a minimum 

 between the full moon and the last quarter (the third, second, or first day before last 

 quarter)." The maximum fluctuated ])etween new moon and first (juarter. 



Investigations relating to "weather shooting'," J. M. Pekntick and W. 

 Tkahkut {Mrinn: /Isrhr. [VirinKi], 17 {IHOO), No. 9, pp. .m?-^/^).— This article 

 describes the construction and gives results of tests of various forms of ai)])aratus 

 used for dis!<ipating hail storms by means of vortex rings. Numerous measurements 

 of the velocity and force of the vortex rings produced by both vertical and horizontal 

 firing are reported and their nature and action are discussed. In the more successful 

 cases of horizontal tiring the rings reached a distance of only about 200 meters, in 

 vertical tiring 300 meters, although sometimes going in the latter case as high as 400 

 meters under exceptionally favorable circumstances. In order that the system may 

 be completely effective the cannon should l)e so placed as to agitate the air to a height 

 of 800 meters, as hail clouds are sometimes that high, though never higher according 

 to Stigcr, Kol)erto, and others. 



WATER—SOILS. 



On the value of e vapor ometric indications to agricultural practice, N. 

 Malushitski {Izv. Moscow Sehk. Khoz. Inst. [Ann. Inst. Agron. Moscoio], 6 {1900), Xo. 

 3, pp. 3^5-403). — The object of the investigation here reported was to find if pos- 

 sible the relation between the evaporation from a free water surface (as indicated 

 by an evaporometer) and that from bare and cultivated (covered) soils. For this 

 purpose the author carried out several lines of experiments, viz: Observations on 

 rainfall and on evaporation from a free water surface, and from soil in large zinc 

 lysimeters, and in small glass lysimeters. 



The evaporation from 'the free water surface was studied with the aid of Michel- 

 son's and of Wild's evaporometers. Wild's apparatus was found more reliable and 

 was used in comparing the evaporation from a free water surface and from the soil. 



In the experiments with the large zinc lysimeters 5 instruments were used. They 

 were filled with soil and subsoil. The author studied with them the evaporation by 

 oats during the whole of its period of vegetation, by rye in the fall period, from 

 black fallow, and from sod (chiefly Aira csespitosa, Veronica latifolia, and Tara.vacum 

 officinale). Since these lysimetei's were heavy (w'eighing 131-1 o9 kg.) and did not 

 admit of accurate weighing, the author also experimented with 12 small glass lysime- 

 ters in which a layer of soil 10-15 cm. thick (corresponding to the medium depth of 

 plowing in case of cereal crops) was placed. On some of the lysimeters rye was 

 grown while the others were left without a crop. 



On the basis of his own experiments and a survey of the whole literature on the 

 subject, the author arrives at the following conclusions: 



(1) The estal)lishment f)f a correlation between the indications of a water evapo- 

 rometer and the evaporation from a cultivated soil under natural conditions is impos- 

 sible, sinc;e the structuri' of the soil and the state of its surface, which are in most 

 cases beyond our control, exert an innnense and varied influence on the stored up 

 humidity as well as on its evaj)oration from tlie soil, an influence which iloes not 

 affect the evaporometer. 



(2) Exceptions may perhaps be admitted in the case of soils (a) .saturated with 

 moisture and (b) possessing a more or less constant amount of moisture with a con- 

 stant structure and unchanging surface. 



(3) The correlation in question can .still less be estal)lished in case of .soil covered 

 with cultivated i)lants on account of the added disturbing factor of the varying evap- 



