112 THE “ROYAL ‘SOCIEDYOF CANADA 
The average number of heat-units and of cold-units for each half 
year at a number of places in Canada will be found in Table I. 
TABLE I. 
Units oF HEAT AND COLD, 1909-12. 








Heat units | Cold units Heat units | Cold units 
Nov.-Apr. | Nov.—Apr. May-Oct. May-Oct. 
Dawson Aliss Veter ates 4,516 155,041 75,968 7,958 
IWIGHOTIAyg a.m rete enon 46,227 1,698 108,666 0 
Barkenvillenr rer) 8,229 53,146 61,255 3, 202 
Edmonton et cn ee 19,072 68,038 97,594 2,120 
OurAppelle rene 12,462 87 ,949 93,392 2 ST. 
NLAMIDERA cashes UN cats 13,053 85,283 113,651 1,613 
Bone Arthurs. nearer cea 11,100 60,910 98 ,005 15252 
POLONtG sen, Men Re RUE 22,726 28,747 130,791 104 
NIONGREA RENE RAR 16,050 46,650 127 ,032 85 
St Olives caren alae oe ea: 17,951 30,995 103,686 43 
ÉTAT MS ENT te 20,341 25,444 112,943 201 
SEB] OLS ee poe eerie 15,293 25,136 91,842 340 


Hourly thermographic records are at present published only 
for Victoria and Toronto, and bi-hourly records for Montreal and 
Quebec. 
While the maximum temperature for the year has no special sig- 
nificance in relation to plant life the minimum temperature is a limiting 
factor in determining the distribution of many species of plants. 
Some species succumb if the thermometer falls to 32° F. while others 
can survive many degrees below zero. The maximum and minimum 
temperatures recorded for the three years 1909-12 are given in Table 
le 
