418 EXPERIMENT STATION RECORD. [Vol.36 



the Canadian agricultural area recently opened. In the southern part of this 

 lobe the problems of low temperature are more commonly blended with problems 

 of low rainfall than is true farther north. . . . The distribution of native 

 vegetation relative to these lines is very marked. . . . The natural factors 

 which give such striking characteristics to the distribution of native vegetation 

 give equally striking characteristics to the distribution of people and the 

 organization of farm business." 



The probable growing season, W. G. Reed {U. S. Mo. Weather Rev., 44 

 {1916), No. 9, pp. 509-512, fig. i).— From a study of data relating to the length 

 of the frostless period from 1872 to 1914 at Keokuk, Iowa, it is concluded that 

 in general " the chance of killing frost falls to 10 per cent between 10 and 30 

 days after the average date of the last killing frost in spring; in the fall the 

 corresponding difference is about the same. In general any station has a dis- 

 persion in spring similar to that in fall." 



Weather insurance, W. G. Reed (U. S. Mo. Weather Rev., 44 {1916), No. 10, 

 pp. 575-580). — In continuation of previous discussions bearing on this subject 

 (E. S. R., 35, p. 617), the author maintains that the cost of losses from un- 

 favorable weather conditions should be carried as an annual charge again.st the 

 farm business. From a study of extensive data relating to the frequency distri- 

 butions of injurious spring and fall frosts in Kansas and Ohio he concludes 

 that sufficient data are now available " to enable determinations of the chance 

 of fi'ost at any time to be made for nearly all the agricultural regions of the 

 United States. Although other phenomena do not show the same frequency 

 distributions as critical frost dates, the distributions for many of these phe- 

 nomena have been partially investigated and the mathematical studies already 

 completed indicate that the chance of any weather condition at all can be deter- 

 mined with more or less accuracy. Therefore practicable insurance against 

 any unfavorable weather depends solely upon the determination of the hazard 

 and a sufficient number of properly distributed risks." 



Condensed meteorological reports, C. C. Geobgeson {Alaska SUis. Rpt. 1915, 

 pp. 93-100). — Tabular monthly summaries are given of observations on tem- 

 perature, precipitation, and condition of the weather at 25 stations in different 

 parts of Alaska during 1915. 



Meteorological observations at the Massachusetts Agricultural Experi- 

 ment Station, J. E. Ostranuer and J. S. Sims {Massachusetts Sta. Met. Buls. 

 335-336 {1916), pp. 4 each). — Summaries of observations at Amherst, Mass., on 

 pressure, teujperature, humidity, precipitation, wind, sunshine, cloudiness, and 

 casual phenomena during November and December, 1916, are presented. The 

 general character of the weather for November is briefly discussed, and the 

 December bulletin gives a summary for the year. The principal data in this 

 summary are as follows : 



Pressure, reduced to freezing and sea level (inches). — Maximum, 30.64, 

 January 8; minimum, 28.76, February 25; mean, 30.006. Air temperature, in 

 ground shelter (degrees F.). — Maximum, 95.5, August 22; Minimum, — 16, 

 February 1.5. Humidity. — Mean dewpoint, 38.4 ; mean relative humidity, 80.8. 

 Precipitation. — Total rainfall or melted snow, 45.61; number of days on which 

 0.01 in. or more rain or melted snow fell, 126 ; total snowfall, 59.5 iu. 

 Weather. — Total cloudiness recorded by sun thermometer, 2,418 hours, or 

 53 per cent; number of clear days, 121. Bright sunshine. — Number of hours 

 recorded, 2,036, or 47 per cent. Wind. — Prevailing direction, west ; total move- 

 ment, 52,150 miles; maximum daily movement, 519 miles, February 28; mini- 

 mum daily movement, miles, December 4; maximum pressure per square 

 foot, 25 lbs., January 23, west. Dates of frost. — Last, May 19; first, September 

 17. Dates of snoiv. — Last, April 14; first, November 15. 



