144 



From A. Ermann's journal of voyage* we select the fol- 

 lowing additions to the geography of plants. In the neigh- 

 bourhood of Tobolsk in 58 northern latitude,, the hilly di- 

 stricts are clothed with dense forests of firs, pines, poplars 

 and very high birch. Near Irkutsk and its environs (52 N. 

 lat.) Pyrus baccata grows, bearing fruit of about the size of a 

 pea, in Kjachta they attain the size of a cherry. Moreover 

 near Neotschinck the true apricot grows with a juiceless peri- 

 carp but well -tasted kernel, and close to it the Siberian Stone- 

 pine. 



M. Ermann gives some very interesting climatological no- 

 tices on Jakutzk (62 lat.) which are of high importance to the 

 geography of plants. The temperature of the soil presented 

 at a depth of 50 feet 6 Reaum. and coincident with this is the 

 mean warmth of the atmosphere f. Every year the tempe- 

 rature falls below 40 Reaum., on the 25th Jan. 1829 even 

 to 46'4 R. The last night-frost occurs on the 1 2th of May, 

 and then the summer lasts till the middle of September. The 

 mean warmth of Jakutzk is in June, July, and August, 1 1, 15, 

 and 13 R., and frequently the thermometer is seen in the 

 shade to mount to 20 R. Several kinds of corn, as summer 

 wheat and rye, are sown in the neighbourhood of the town, 

 and bear 15-, and even in some cases 40-fold, although the soil 

 is thawed only to a depth of 3 feet. In the gardens po- 

 tatoes, cabbages, turnips, and radishes are cultivated, and even 

 cucumbers are forced in dung beds. 



The isothermal lines do not extend from the Lena straight 

 eastwards, but ascend strongly towards the north. Near 

 Antscha, one degree north of St. Petersburg, and 2244 Pa- 

 risian feet above the sea, the vegetation was more luxuriant 

 than the summit of the Brocken in the Hartz. Lofty-stemmed 

 trees (not coniferous) graced the forests. In the journey across 

 the Aldamic Mountains Betula nana was frequently met with, 

 which is more sensitive than the larch to the cold mountain 

 air. At 3444 Par. feet near the end of the Antscha valley 

 several larches were found, by which the relations of tempe- 



* Reise um die Erde durch Nord-Asien und der beiden Oceane in den 

 Jahren 18281830, erste Abtheilung. 



f The ground ice there is said according to recent communications to be 

 382 feet thick. 



