Vegetable ProducUons of the HudsorCs Bay Countries, ^05 
RemarTcs on the preceding Tables,, principally with a reference 
to the Climate (f Cumberland House. 
Humboldt informs us, that “ in all places whose mean tem- 
perature is below 6^°.6, the revival of nature takes place in 
spring, in that month whose mean temperature reaches 42°. 8 or 
46°.4. When a month rises to 
41°.95 the peach-tree ( Amygdalus Persica ) blossoms ; 
46 .8, the plum-tree ( Prunus domestica ) blossoms ; 
51 .8, the birch-tree ( Betula alba ) pushes out leaves. 
“ Barley, in order to be cultivated to advantage, requires du- 
ring ninety days, a mean temperature of from 47° 3 to 48°.2. 
In reference to the culture of useful vegetables, we must 
discuss three things for each climate ; the mean temperature of 
the entire summer, that of the warmest month, and that of the 
coldest month. 
“ By adding the mean temperatures of the months that rise 
above 51°.8, that is the temperature of the months in which 
trees with deciduous leaves vegetate, we shall have a sufficient- 
ly exact measure of the strength and continuance of vegeta- 
tion.” 
Wahlenberg has also remarked in his Flora Lapponica^ that 
the air must acquire a mean temperature of 4° centigrade, or 
39°«20 Fahr., before the frozen rivers break completely up.” 
The River Saskatchawan, which flows about two miles an 
hour at Cumberland House, broke up on the 28th April 1820, 
the mean temperature of the ten preceding days having reached 
only 36° ; but it is to be noticed, that one of the principal 
.branches of this river rises in a more southerly latitude. 
The narrow but deep streams which flow from Pine Island 
Lake, on which Cumberland House stands, into the Saska- 
tchawan, did not freeze at any time during the winter ; a cir- 
cumstance to be attributed to their receiving a constant supply 
of warm water from the bottom of the lake. The lake itself 
was covered with ice about three feet thick. 
The phenomena of spring, however, are perhaps most readily 
exhibited in a tabular form. 
