S84 Analyses of Books. [May, 
North Latitude, 45°—47°. 
Height Ann. Mean Mean 
im mean of coldest of hottest 
fathoms. temp. month, month, 
Sea’ shore? ..82. es. e 5 OO", AS Sess, OS BaP siprO? 
Geneva . OF BE SDDS AN) VBI OLE GEGE FQ SED o eT Oe 
"Fegernsee oh ee 382 2) YL BRS) PO SU PTS 2 
Peidenbiers (MVS. DUOFEM) 9, 0 DAO! De, ISD 
C@hamouix. i 2.00.2... 528 oe Ae Js. PSO 
Monastery of St. Gothard..1065 ....—0°9 .. —94 ....7°9 
Col de Geant ...:. HELL. P7E3 [FEI 68 8. ces 25 
In the temperate zone of our Continent, when the mean heat of 
the month amounts to 
5*5° the amygdalus persica blossoms 
$2 prunus domestica 
“ 11:0 betula alba. 
At Rome the mean temperature is 11° at the end of March; at 
Philadelphia, in April; at Paris, in May; at Upsala, in the middle 
of June. At the monastery of St. Gothard the betula alba cannot 
blossom, because the mean heat of the hottest month scarcely 
amounts to 9°. Between north latitude 40° and 60°, the hottest 
month adds about ‘#° to the mean temperature of the year; and 
beyond 60° the addition is greater. 
In mount Caucasus, between latitude 42° and 43°, the lower 
limit of perpetual snow is at the height of 1650 fathoms. In the 
Pyrenees, between latitude 424° and 43° the lower limit of per- 
petual snow is at the height of 1400 fathoms. In the-Alps, between 
latitude 453° and 561°, it is at the height of 1370 fathoms. Hum- 
boldt gives the height to which different plants reach on these 
mountains, and we are sorry our limits will not allow us to insert 
them here. 
In the temperate zone, as we advance northwards, the coldness 
of the winter increases at a much greater rate than the heat of the 
summer diminishes. ‘Thus at Enonlekis, in latitude 681°, the 
temperature of July is as hot as at Edinburgh; but between the 
tropics, the temperature on mountains at no season of the year 
equals that at the sea shore. Hence in the temperate zone we find 
the same plants frequently in low and elevated situations; but this 
is never the case between the tropics. 
In Lapland, between latitude 674° and 70°, the inferior limit of 
perpetual snow is at the height of 550 fathoms. 
The reason why plants vegetate with so much greater rapidity in 
Lapland and Norway than further south, is because the increment 
of temperature is much greater, and because the temperature of 
the earth in winter is several degrees above that of the air. The 
following table exhibits the most remarkable circumstances re- 
specting temperature in the three different zones, 
