628 TRANSACTIONS OF SECTION E. 



Spring is sudden and short, being limited, as far as wheat-cultivation is con- 

 cerned, to the four weeks in April, wlien there is an average daily maximum of 

 about 50" F., the east being 5° colder than the west, where snow is not ' packed,' 

 and is therefore easily licked up by the chinooks. 



With unit of population = one family of live persons (at least two of them 

 males), the maximum of plough, harrow, and drill that can be * risked ' = 80 acres 

 in the four weeks. 



Summer is the rainy season, beginning with mid-May rains and ceasing with 

 mid-August dry spell. Temperature rises steadily May-June with rain : Winni- 

 peg district has more than half, QuAppelle and Prince Albert districts have more 

 than three-quarters, of the total rainfall in the three ' growing ' months (May, 

 June, July). 



Mean temperature (June- August) on Brandon-Battleford curve is 62°'5 = that 

 of best English wheat land. 



Duration of sunlight varies from about 16^ hours per day at mid-summer in 

 Winnipeg district (averaging one hour per day more than Chicago district from 

 June 15 to July 1) to over 17 hours at Prince Albert, with very high percentage 

 of bright sunshine (result, a fine-coloured grain), especially along Brandon-Battle- 

 ford curve. 



Duration of night. — Short night = short time for radiation, but comparatively 

 long ' cool ' spell, which is as favourable to wheat as it is unfavourable to maize 

 (and mosquitos). 



Autumn is a dry season : (a) August, harvest. One family can bind and stook 

 70-80 acres in one week (if there is a third male can cart same in a second 

 week to central stack, and have the equivalent of 1,200 bushels of grain ready for 

 thresher by the end of August) ; (6) September, average temperature drops 10° F., 

 and 70 hours of bright sun is lost; October drops 10° F. more. Therefore it is 

 desirable to plough at once. Loss of ' fall ' plough means loss of early seeding 

 the following year, = loss of yield per acre, loss of weight per bushel, loss of market 

 by water transport. 



Winter.— Length and intensity of cold do not affect tlie north limit of wheat 

 in summer, but guarantee cleansing of ploughed land and leave no excuse for 

 grain not being also clean. 



5. The Zambezi beyond the Falls. 

 By A. Trkvor-Battye, M.A., F.L.S., F.R6.S. 



