Vegetable Productions of the Hudson^s Bay €ountries. SIS 
and agree sufficiently near with the following interpolations ; from 
which, however, the chilling effect of the icy covering of both 
lakes, in spring, is excluded. 
Table VIIT. Interpolated from Table II. 
SEASONS. 
Athabasa, 
Lat. S8| N. 
Long, nil 
W. 
Slave Lake, 
Lat. 61| N. 
Long. 113:1 
W. 
Six summer months, April, — September, 
Six winter months, October, — March, , 
Spring. March, April, and May, 
Summer. June, July, August, . . . , 
Autumn. September, October, November, 
Winter, December, January, February, 
+ 47°-33 
— 0 40 
+ 20 -61 
+ 60 -16 
+ 26 -ST 
— 13 -36 
-1- 43°*24 
— 4 44 
+ 15 -52 
+ 5T • 0 
-j- 23 *59 
— 18 *00 
Mean annual temperature. 
+ 83‘’'56 
-1- 19“-53 
Table IX. Interpolated from Table I. 
SITUATION. 
Mean Temperatures. 
May, 
June, 
July. 
Aug. 
Athabasca, Lat. 58| N., 
Slave Lake, 61^ N., . « « 
41°‘0 
3T -2 
53°-6 
50 ‘6 
62°'0 
60 -5 
64'’*5 
60 -0 
These Tables shew, that, at Athabasca, there are three months 
which reach 5l°‘8, and that their united mean temperatures 
amount to 180°. At Slave Lake, there are only two months that 
attain that height ; and the sum of their mean temperatures is 
1S0°. At Slave Lake, in the year 18SS, it was nearly the end 
of IMay before the mean temperature of any considerable number 
of days reached the vernal temperature of 4S°‘8. On the S5th 
of that month, Slave Kiver broke up, the passage of the lake 
over the ice being at that time considered unsafe. From the 
25th of May to the 2d of June, we observed, on the voyage to 
Fort Chepewyan, willows, gooseberries, the Anemone Nuttalliana 
(D.C.), Aronia ovalis, Prunus Virginiana, and Hi ppophde Cana- 
densis, flowering nearly in the order in which they are here men- 
tioned. The leaves were also rapidly evolving at this period, in 
perfect accordance with Humboldt's observations as to the tem- 
perature required. 
VOL. XU. NO. 24. APRIL 1825. p 
