1816.] Humloldt’s, &c. Plants of South America. 883 
grow. The mean temperatures in the two hemispheres do not 
differ so much from each other as the summer temperatures. In. 
south. latitude -48° the summer temperature is equal to the winter 
temperature of Toulon, Cadiz, and Rome. 
Mountains 1000 fathoms*in height at latitude 46°, enjoy. the 
mean temperature of Lapland, while the same heights between: 
the tropics enjoy the temperature of Sicily and Calabria: for. this 
height occasions a diminution of temperature amounting to 12°! 
Hence 500 fathoms correspond with 9° 30’ of latitude; so that 50 
fathoms is very nearly equivalent to half a degree of latitude. 
We regret that we cannot insert here Humboldt’s catalogue of 
the distribution of plants within the tropics of South America, 
according to the height of the different places above the level of. 
the sea; but the following table exhibits the mean temperature at 
different heights between the tropics in the new Continent. 
South America, Mexico, 
Height injbetween lat, 0° and 10°, S. and N. between lat, 17°—219, N, 
fathoms, 
Mean ann, {Var. in the temp. of | Mean ann, | Var. in the temp. of 
temp. the whole year. temp. the whole year, 
O} 27:5° | 11°5°Cumana | 26°  /|16° Vera Cruz 
500 | 20°5 12°7 Caracas 19°8 Encero 
1000 | 180 Popayan | 18 22 Valladolid 
1500 | 13°5 16 Quito 14 Real del Monte 
2000 6°8 75 ; 
2500 15 19 Pichinca | —1 
The higher we ascend above the level of the sea, and the further 
we advance from the equator, the greater is the difference between 
the temperature of the different seasons of the year. The following 
table exhibits the difference between the mean temperature of the 
two hottest and coldest months in different latitudes. 
Lat. 
SAMOA Shs wales hs dt eee OPO 
Wey Wi a Ua kk ee as Salk. oy ane 
FURVENOGN vo a pa ino SO... 6 foatcnn dias LA 
INBLCHEZ © Uip'uv peed OR Te bine, eins hers. 
Philadelphia ...... 39 56 ........ 246 
MEMCOCE oo cbt ttn: et WET eh ck chee, SRD 
Wait a) 6 SAPO: My RE Rea 7, | : 
‘The temperature of elevated situations in Europe is not so well 
known as in South America, where there are cities at a greater 
height than the top of the Pyrenees, and houses more elevated than 
the summit of the Peak of Teneriffe. The following table contains 
the facts which Humboldt has been able to collect on the subject :— 
