— 51 — 



We have an interesting province from a climatic point of view for the great 

 estuary of the St. Lawrence has an important influence in modifying the intensity 

 of the larger controlling factors of latitude and altitude. I believe I am not too 

 optimistic in stating that if the local influences of topography, exposure, prevail- 

 mg winds, sunshine, rain, soil, etc., were thoroughly studied, many important im- 

 provements could be effected in the growing of crops. As Hopkins says: "There 

 is a northern, southern, and altitudinal limit to the profitable culture of crops 

 between which the^e is an optimum zone for the most profitable culture. By 

 means of computing tables these limits and optimums can be approximately de- 

 termined and shown on maps to serve as a guide to research and practice in de- 

 termining the facts as related to regional and local conditions." 



The Bioclimatic Law. 



This law represents the "general Iaw> of climate as affecting the seasonal 

 activities and geographical distribution of plants and animals, periodical practices 

 in Agriculture and the adaptation of farm crops to the requirements of climatic 

 conditions." It may be stated as follows: The variation in the time in which per- 

 iodical events occur in the seasonal development and habits of plants and animals, 

 at different geographical positions within the range of their distribution is, other 

 things beings equal, at tJic rate of four days for each degree of latitude, five de- 

 grees of longitude or four hundred feet of altitude. 



Accordingly, lines running from the east toward the northwest at the rate of 

 one degree of latitude to five degrees of longitude represent the same constant or 

 average date of a periodical phenomenon for any given level throughout the 

 length. Such lines Hopkins calls isoplmnes. He has constructed an isophanal map 

 of the United States, with phenological meridians, five degrees apart but at right 

 angles to the isophanes. By means of an accompanying chart for altitude he shows 

 how constants may be computed, for the three combined factors, latitude, longi- 

 tude and altitude. As the effect of local accelerating or retarding influences 

 such as topography, lakes, large rivers, winds, etc., modify the computed average 

 of the constant for each quadrangle, such departures for both spring and autumn 

 have been determined and marked on each quadrangle of the isophanal map. Such 

 determinations were based on 40,000 reports from all parts of the country on the 

 beginning of wheat harvest. 



A detailed study of the altitude limits of species and of biological associa- 

 tions of plants and animals as mapped by the U. S. federal and state biological 

 surveys served not only to verify the evidence furnished by the wheat harvest re- 

 cords but to establish, as a general principle, the approximate amount of variation 

 we may expect to find in all regions from those in which there is no perceptible 

 retarding or accelerating influence to those where the intensity of the influences 

 reaches its maximum. 



