416 EXPERIMENT STATION RECORD. [Vol. 38 



States are tabulated and discussed, and maps are presented which show (1) 

 the average dates of the last killing frost in the spring and the first in the fall 

 in the United States, (2) the average frostless period, (3) the probable occur- 

 rence of the last killing frost in spring and the first killing frost in the fall in 

 one year in ten, and (4) the probable length of the season without killing 

 frost in four years out of five. The business risk involved in planting and har- 

 vesting at particular times is discussed. 



Snow surveying-: Its problems and their present phases with reference to 

 Mount Kose, Nevada, and vicinity, J. B. Church, je. {Proc. 2. Pan Amer. Sci. 

 Cong., 1915-16, vol. 2, pp. 496-549, pi. 1, figs. 3). — The methods and apparatus 

 used by the author in measuring snow and the evaporation from snow fields 

 are described in detail, and the application of the i-esults in forecasting the 

 probable water supply for irrigation is fully discussed. Special attention is 

 given to methods of forecasting, based on seasonal percentage surveys, in 

 which the object is to determine the percentage relationship of a given .season's 

 snowfall to that which normally occurs in a watershed applying " the resulting 

 percentage to the normal run-off as measured at the outlet of the basin." 



These studies have been noted from time to time from other sources (E. S. 11., 

 36, p. 17; 37, p. 16). 



Snow and its value to the fanner, A. H. Palmee {Sci. Mo., 6 (1918), No. 2, 

 pp. 128-141, fiys. 18). — It is pointed out in this article that, "as a blanket or 

 covering, snow on the ground checks winterkilling. It protects vegetation from 

 extreme temperatures, from excessive evaporation, and from destructive winds, 

 at the same time permitting the penetration of some sunlight and allowing 

 uninterrupted respiration of plant ti.ssue. On twigs and buds it conserves 

 cellular moisture which otherwise might be sacrificed at too rapid a I'ate dur- 

 ing sudden changes of temperature. It mellows the soil, replenishes the ground 

 moisture, checks the run-off from winter rains, furnishes most of the water 

 used for irrigation and power purposes, provides an easy means of transpor- 

 tation, and prevents destructive prairie and forest fires. Grass is benefitted 

 by abundant snows, and winter wheat is largely dependent upon it for its 

 success." 



Nitrogen, chlorin, and sulphates in rain and snow, B. L. Peck (Chem. 

 News, 116 (1911), No. 3029, pp. 283, 284).— The data contained in a continua- 

 tion from October 20, 1916, to June 8, 1917, of studies on this subject at Cor- 

 nell College, Iowa, are reported in detail (E. S. R., 34, p. 615). 



Weather review for 1914 and 1915, W. M. Esten (Connecticut Storrs Stu. 

 Rpt. 1914-15, pp. 255-270, fig. 1). — Observations at Storrs, Conn., on tempera- 

 ture, precipitation, and length of the growing season are summarized and tables 

 are given which show the monthly and annual means of temperature and 

 precipitation, 18S8 to 1914, and length of the growing season, 1888 to 1915. 



The mean temperature for 28 years, 1888 to 1915, was 47.47° F. ; highest 

 temperature, 99°, July 3, 1912; lowest temperature, — 17°, February 14, 1914; 

 mean rainfall, 44.17 in. ; longest duration of growing season 184 days, April 18 

 to October 19, 1901 ; average date of last killing frost in spring. May 3 ; average 

 date of first killing frost in autumn, October 10; and prevailing wind in Janu%i"y, 

 February, March, April, May, August, October, November, and December, 

 northwest ; in June, July, and September, southwest ; and for the year, 

 northwest. 



Annual report of Iowa weather and crop bureau for 1916, G. M. Chappel 

 (Iowa Yearbook Agr., 17 (1916), pp. 514-573, 579-582, figs. 9).— This report is 

 made up of the summaries of the monthly and weekly bulletins issued by the 

 Iowa Weather and Crop Service in cooperation with the Weather Bureau of 

 the U, S. Department of Agriculture. 



