4 LETTER FROM M. E. BOURGEAU, 
at Carlton: the species are not numerous, for which reason I 
have collected both male and female specimens of each plant, and 
have been careful to put corresponding numbers on each ser. 
There are а good many duplicates; therefore I trust you may 
have as many specimens as will enable you to study them satis- 
factorily. I regret not being able to send you the leaves of the 
Salices; they are not yet developed. During the third week of 
` last month, the catkins of P. balsamifera have been frozen and 
have fallen off; several other plants, also in flower, have been 
frozen, and thus for a week I have been deprived of my ex- 
cursions. 
Observations referred to in the foregoing Letter, on the Tempera- 
ture of the Earth and of Forest-trees, made at Fort Carlton, 
on the Saskatchewan. 
Date. | 1 feet. 3 feet. Populus. Abies. Atmosphere. 
1857. o o o o o 
Nov. 1 39'0 41'0 em AP 375 
39°0 4r$ i» ee cove 27°0 
3 39°0 41'5 T" sees 36:0 
4 390 40° Т eA eves 
i 39°0 40'0 "T TED v. 
39°0 40°0 "TER А 26:0 
7] 380 397 . 250 
8 375 39°0 150 
9 379 39°0 21°5 
| 10 379 39°0 15"0 
11 370 39°0 25°0 
12 365 38°5 26°0 
13| 360 38°0 250 
14 360 380 3ro 
15 360 380 22'0 
16) 35'5 375 317 
17 35°0 37°0 29°0 
{ 35'0 370 . 2270 
ї 35°0 37°0 . 2'0 
зо 347 367 340 
э 345 365 + ro 
22 34'0 36°0 зо 
23) 337 3670 240 
| 24 340 36°0 14°0 
25 33°5 35°5 10°0 
26 330 350 130 
27 330 350 25°0 
28 330 350 18*o 
29 330 350 130 
330 35°0 » 12°0 
Dec. 1| 330 350 17°0 
2 32°5 350 17*0 13°0 
3 32°0 34°0 g'o — ro 
4 3270 340 70 10°5 
5 32°0 44°0 11'O 170 
6| 320 340 12'0 15'0 
