262 Obsei'vatiotis on Humboldt's Works 



A third error, which the author endeavours to correct, is 

 this, that the southern hemisphere is altogether colder than the 

 northern. He shews that this prevails only in the part beyond 

 the tropic. 



6. The Influence of different Altitudes upon Ve- 

 getation IN the different Zones of the Earth. — 

 (p. xxxiii. — ^liv.) 



The author, in the first place, presents a view of the varieties 

 which regions of different altitude afford, in respect to climate 

 and vegetation in the equatorial zone (in America). These 

 varieties are given first for the zone between 0° and 10°, and 

 then for that between 17° and 21° of latitude, and in both 

 zones, in respect to altitude, three regions are considered ; 

 regie calida, temper ata^ etfrigida. It might, perhaps, be thought 

 that the hot region, which rises to 200 toises, is too circum- 

 scribed, to be compared with the torrid zone ; but, if we take 

 into consideration, a remark made by the author, which I shall 

 mention presently, this probably is not the case. On the other 

 hand, we cannot suppose that the temperate region under 

 17 — 20° of latitude, commences at the same height as 

 under 0—10°. 



After this view of the equatorial zone, the author takes notice 

 of the varieties, which difference of altitude produces in the 

 temperate and frigid zones ; for instance, in the Pyrenees, in 

 the Caucasus, in Switzerland and in Lapland, according to 

 Ramond, Engelhardt, Parrot, and Wahlenberg. I 

 have to remark in this place, that the author places the limits 

 oi Betula Alha upon the Caucasus, at 1,050 toises, although, 

 according to Engelhardt and Parrot *, this tree, in one 

 place only, under very favourable circumstances, advanced to 

 that height. According to them its mean height (which only 

 we are to consider here) is 870 toises. 



All the results are represented in a table, p. xlix., by means 

 of which a comparative view is afforded of the relations in 



* Reise in die Krimm und den Kaukasus. 



