




[ADAMS] CLIMATIC FACTORS IN RELATION TO PLANT LIFE 115 
TABLE IV. 
FROSTLESS PERIOD, 1910-12. 
Average 
Last frost in spring. First frost in autumn. length 
in days. 
Dawson. 2 June to 28 June 18 Aug. to 23 Aug. 67 
Victomia ere 5 Apr. to 17 Apr. 8 Nov. to 31 Dec. 233 
Barkerville....... 9 June to 12 July 8 Aug. to 29 Aug. 53 
Edmonton. .--. .- 12 May to 13 June 6 Sept. to 14 Sept. 104 
Qu’Appelle....... 21 May to 3 June 26 Aug. to 15 Sept. 100 
Winnipeg........ 12 May to 2 June 28 Aug. to 26 Sept. 118 
Por arthur... 13 May to 3 June 12 Sept. to 27 Sept. 118 
HMorontO re 4 May to 15 May 16 Oct. to 29 Oct. 165 
Montreale=...".. 28 Apr. to 4 May 16 Oct. to 29 Oct. 176 
SElohn ie eee 29 Apr. to 6 May 310ct.) to L'AOcT. 161 
ISRINESS. Ganga bee 17 May to 23 May 15 Sept. to 4 Oct. 130 
Steeloumiss: oe. 24 May AOct to 12, Oct; 126 
to 7 June | 


In making observations on frosts considerable differences will 
be found at different heights above the ground. Thus Koslovskii® 
who experimented with seven thermometers placed at different heights 
above the ground found that the minimum temperature was recorded 
between 2 and 3 feet above the surface of the soil. 
Instead of estimating the mean temperature of the hottest six 
weeks as suggested by Merriam the number of days of tropical heat 
are given. 
A day with tropical heat is defined as a day with a mean 
temperature of 68° F. or over and the figures are given in Table V. 
TABLE V. 
DAYS WITH TROPICAL HEAT, 1910-12. 
AW SO RS Sia iG SNE eee Saas ei Be Ne a ut 1 
WAU GI TEE ihe oc sconce Eg ce CHS Te RE REEL RE One gr ns 4 
RACE VALEUR aera RI Fook is tise celta RS rre 1 in three years. 
ESCM O MEO Meee es ye MeN RENE RE a eee Seen 7 
(One A ES RS REPAS ch War «a hag sec lal Sic sin ne 14 
PN MSTA ease ee ay ne non return x Droue 5 nove le ike 28 
OR ANNE vo SRE RE Re EE eee 9 
ÉRORON TO EPP RER TERRE ARR RARE NS ee 45 
Montrealers pert ees EL PA tea AE A es te 37 
DEMO EN AR SE Were da ines Biot alo rat ds 6 
OC er? SO 22 
SA OUT MOIS à RC ER RE RE EE uf 
18 Bull. Bur. Agric. Int. 3: 1926. 
1912. 
