418 EXPERIMENT STATION RECORD. 



untarctic regions upon Draysoii'.s theory that the earth lias a second rotation 

 besides the diurnal one, and that this secondary rotation has a cycle of 31,G82 

 years during which the obliquity of the earth's axis varies from a minimum of 

 23° 25' 47" to a maximum of 35° 25' 47". According to this theory the earth 

 is " now some 15,450 years removed from the height of the glacial period, when 

 the contrast between summer and winter in temperate latitudes was inconceiv- 

 ably great and only 3S5 years removed from the j)ositiou of minimum obliquity 

 when the contrast between (he seasons will be least.' 



Meteorological observations at the Massachusetts Agricultural Experi- 

 ment Station, J. E. Ostrandkr and R. E. McLain (Massachusetts Sta. Met. 

 Bills. 311, 312 (UI14), pp. 4 each). — Summaries of observations on pressure, 

 temperature, humidity, precipitation, wind, sunshine, cloudiness, and causal 

 phenomena during November and December, 1914, are presented. The general 

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

 bulletin gives a summary for the year. The ]»rincipal data in this summary 

 are as follows : 



Pressure, reduced to freezing and sea level (inches). — Maximum, 30.78, 

 November 29; minimum, 28.47, March 1; mean, 30.048. Air temperature, in 

 ground shelter (degrees F.). — Maximum, 9G.5, September 22; Minimum, —18.5, 

 December 27. Ilumidity. — Mean dew-point, 36.6; mean relative humidity, 75.8. 

 Precipitation. — Total rainfall or melted snow, 41.83; number of days on which 

 0.01 in. or more rain or melted snow fell, 118; total snowfall, 56.75 in. 

 Weather. — Total cloudiness recorded by sun thermometer, 2,077 hours, or 47 per 

 cent; number of clear days, 100. Bright sunshine. — Number of hours recorded, 

 2,377, or 53 per cent. Wind. — Prevailing dii'ection, west-northwest ; total move- 

 ment, 55,455 miles; maximum daily movement, 4SS miles, January 13; minimum 

 daily movement, 1 mile, December 28; maximum pressure per square foot, 30 

 lbs., March 1, east. Dates of frost. — Last, May 16; first, September 28. Dates 

 of snow. — Last, April 16; first, October 27. 



Notes on the climate of historical times with a summary of mediaeval 

 weather phenomena, A. Norlind {Lunds Univ. Arsskr., n. ser.. Sect. 1, 10 

 (WUf), Xo. 1, pp. 55; al}s. in Geogr. Jour., 45 {1915), No. 1, p. 82).— X table 

 containing available data regarding weather conditions in Europe during the 

 period from 709 to 1499 is given with refei-ences to the original records from 

 which the data were obtained. Certain outstanding climatic events, such as 

 the freezing of the Baltic aud Kattegat and the floods on the coast of Friesiau 

 Germany, receive particular attention. A detailed comparison is made of the 

 winter and summer weather for each year for which there ax"e data, between 

 1121 and 1310, and a chart based on ten-year averages of the succession of 

 severe winters and moist cool summers is given. 



It is shown, in general, that the summer was usually cold and wet when the 

 winter was mild. A certain periodicity with winter maxima at intervals of 

 25, 45. 50, and 35 ( ?) years is also indicated. 



While the data are considered iusuffioient to demonstrate the fact, the 

 author is inclined to believe that the winter was formerly colder than at 

 present, though to an insignificant extent. In general, the weather appears to 

 have been practically uniform throughout the historic period; at least that 

 there have been nothing more than very slight changes from the existing 

 conditions. 



[Meteorological observations in Canada], J. II. Grisdale et al. (Canada 

 Expt. Farms Rpts. WIS, pp. 3, .',, 16-19, 72, 76, SI, S2, S5, 88, 91, 92, 95. 103, 

 lOJ,. 113. 131. 13.',. 137, 160, 161. 175-177. 187. 190, 191. 2/S).— Brief summaries 

 are given of weather conditions aud of observations mtiiuly ou temperature and 



