160 THE CANADIAN NATURALIST. [Vol. viil. 



of the human race. Wherever the geologist can explore the 

 earth's surface, he can read much of its past history, and can 

 determine approximately its latest movements above and below 

 sea-level ; but wherever oceans and seas now extend, he can do 

 nothing but speculate on the very limited data afforded by the 

 depth of the waters. Here the naturalist steps in, and enables 

 him to fill up this great gap in the past history of the earth." 



THE WINTERS OF 1874-75 and 1875-76. 

 By C. H. McLeod, Bac. App. Sc. 



The saying " it's all in a bag and must come out," so fre- 

 quently applied to the weather, is in a certain sense true, but we 

 must not be in too great a hurry for the bag to empty itself. 

 This meteoric sack, so to speak, disgorges its contents in an 

 intermittent sort of fashion — now we have heat above the nor- 

 mal, and again an excess of cold. The velocity of discharge 

 varies throughout a day, varies continually ; the means of the 

 elements for a day exceed or fall below those on either side of it, 

 so also the means for a year show a marked difference from that 

 preceding or following it, and the average temperature or rainfall 

 of one season often bears but little resemblance to the same 

 period in another year. On the other hand, given a period of 

 from five to ten years, it is found that the mean of any element 

 for that time does not differ materially from those derived from 

 any other similar period. It therefore takes several years for 

 the truth of the saying above quoted to be verified, and when 

 after continuous observation of an element for the required time y 

 an average or mean for that element is determined, the normal 

 proper to the place and any given time is said to be known ; and 

 this is the average of what we have chosen to term velocity of 

 discharge — to be so determined for each and all of the meteoro- 

 logical elements. 



How much one of our seasons may differ from another has 

 been most markedly illustrated during the past two winters and 

 it is to that we propose calling attention at present. 



