Prof. J. Le Conte on the Freezing of Vegetables. 201 
frozen at this period of the year, and, consequently, that such an 
accident is not always injurious to vegetation.* ~~ 
Neither is the example of Yakutsk an iso 
thermal line of 32° Fahr., support extensive forests of birch, 
(Betula alba,) Norway spruce, (Pinus abies,) larch, (P. larix,) - 
Cembra pine, (P. cembra,) Scotch fir, (P. sylvestris, ) white spruce, 
(P. alba,) American silver fir, (P. balsamea,) and black spruce fir, 
(P. nigra,) where the ground-ice is perpetual.t These facts ap- 
ing and fructification, provided the summer be hot enough, and 
of sufficient duration. tus 
But it may be objected, that when the sap contained in the 
trunks of trees becomes frozen, it cleaves them with a great noise, 
—a phenomenon not uncommon in high latitudes,—and that, 
therefore, the fact that the majority of them are not thus cleft, 
proves that their juices have not been congealed. It is proper to 
remark, en passant, that even in the cases where the trunks of 
such a result, provided all parts of the tree were perfectly rigid 
' * The lowest temperature that has yet been observed on the earth, is probably 
that noted by Savecutt at this same (Yakutsk) on the 2ist of ger es 
“The instruments used in this operation were compared with his own by Midden- 
dort, operations are always cond with extreme exactitude. Neverofft 
found the temperature on the day above-named, = ahr. ne 
Cosmos, (Bohn’s Scientific Library,) translated from the German by ONG 
43. London, 1851.) The maximum natural cold previously recorded, is — 
iii, p. 5 
Fahr.; being that observed by Capt Back at. Fort Reliance in January, 1834. 
+ Vide Johnston’s Physical Atlas. ; : ee tat RR 
+ Vide Travels in Siberia, Hd. eit. supra, vol.ii,p. $60. 
Secoxo Snares, Vol. XIII, No. 88—March, 1852.86 
wi 
¢ 
