20 EXPERIMENT STATION KECOED. 



year of the period of observation. "The percentages of concentration for the 

 separate constituents, however, show some variation from the general rate of 

 concentration, due, undoubtedly, to the disturbing effects of drainage and 

 seepage water received by the lalie. Three constituents — calcium, potassium, 

 and carbonic acid — are showing variations clearly not due to these causes. 

 Calcium and carbonates, as in previous years, have not concentrated as much 

 as the other constituents, carbonates again showing an actual decrease. It 

 is now well established that this loss of calcium carbonate is due to the 

 formation of new travertines similar to those formed when the ancient Salton 

 Sea dried up. Potassium, however, instead of decreasing, has concentrated 

 this year in about the same ratio as the other constituents. This may be ac- 

 counted for in part by the apparent decrease in animal and vegetable organisms 

 in the v,'atei\" 



The rainfall of the cotton belt of the United States and its results, B. C 

 Wallis {Scot. Geogr. Mag., 31 (1915), No. 2, pp. 11-19, figs. 5).— This is an 

 account of a study similar to that of the rainfall conditions of the northeastern 

 United States, which has already been noted (E. S. R., 32, p. 119). 



It Is shown that the rainfall of the cotton belt varies widely, the average 

 annual rainfall being 31 in. in the west and 54 in. in the southeast. There is 

 apparently a direct relation between rainfall and temperature, an average 

 low-temperature meaning, as a rule, a small amount of precipitation. Correlat- 

 ing rainfall with crop growth, the conclusion is reached " that the best condi- 

 tions for growing cotton occur about latitude 32° N. in an area where the 

 total annual rainfall is about 50 in. per annum, where the temperature is nor- 

 mal and therefore almost entirely a function of the latitude, and where the crop 

 rainfall depends upon the rising temperature and upon the slacking effect of 

 oceanic influences, so that an average rainfall of 20 in. can readily be obtained 

 during the five or six months required for the growth of the cotton plant." 



The relation of rainfall to other crops grown in the cotton belt is also 

 briefly considered. 



Isomeric rainfall maps of the British. Isles, H. R. Mill and C. Salter 

 (Quart. Jour. Roy. Met. Soc. [London], J,l (1915), No. 173, pp. l-'i'f, figs. 19; 

 ahs. in Geogr. Jour., 1^5 (1915), No. 6, pp. 520-522). — A series of isomeric maps 

 based upon rainfall records at 283 places, in most cases covering 35 years (1875 

 to 1909) and in no case less than 30 years, is given and their significance ex- 

 plained. 



Seasonal distribution of rainfall in the British Isles (Geogr. Jour., Jf5 

 (1915), No. 6,,i)p. 520-522). — The character of the seasonal variation of rainfall 

 in the British Isles is described as bi-phase; "for whereas on the one hand 

 there is a percentage excess in the wet, hilly, western parts of the country dur- 

 ing the winter half of the year (October to March), with maximum in Decem- 

 ber and January, and a percentage excess in the dry, flat, eastern parts during 

 the summer half (April to September), with maximum in July, on the other 

 hand, throughout the country the isomeric values are lower during the spring 

 half-year (January to June), with minimum in April, than during the autumn 

 half (July to December), with maximum in October." 



Atlas of agricultural meteorology. — I, Probability of droughts in Euro- 

 pean Bussia, P. I. Bkounov (Atlasy po Selskokhoziaistvennol MeteorologU. 

 Yypusk I. SkhematichesMia, Karty YQroiatnosti Nastuplen'iia ZasushlivyJch 

 DeJcad V Evropelskol Ross'ii. St. Petershurg: Met. Bur., 1913, pp. 7, pis. 21; 

 ais. in Zhur. Opytn. Agron. (Russ. Jour. Expt. Landnv.), 14 (1913), No. 6, pp. 

 663, 664). — The atlas consists of a brief explanatory text with 21 maps char- 



