THE ISTHMUS OF PANAMA. 235 
in succession, and are accompanied by thunder and lightning of the most 
terrific description. The air is loaded with moisture and fogs; calms 
and light variable winds prevail. The temperature does not vary more 
than from 75° to 87° Fahr., but still, the perspiration being impeded, 
the atmosphere feels exceedingly hot and close. Towards the end of 
December, the violent rains diminish in frequency, the clouds begin to 
disperse, and with the commencement of the new year the N.W. wind 
sets in. An immediate change follows. The air becomes pure and re- 
freshing, the sun brilliant, the sky blue and serene, hardly a cloud is to 
be seen, and the climate exhibits all its tropical beauties. The heat, 
although much greater, ranging between 75° and 94° Fahr., is less felt, 
because the atmosphere is almost free from moisture. The rays of the 
sun, however, bear very great power: and the rising of the thermometer 
to 124° Fahr., when it is at noon exposed to their influence, is no un- 
common phenomenon. These observations, however, only refer to the 
lower regions ; on the higher mountains the climate is, of course, sub- 
ject to various modifications, and better adapted, on account of its lower - 
temperature, to an European constitution. 
A country so much visited by heavy rains, naturally abounds in rivers. 
Not counting the smaller streams and ravine torrents, their number 
cannot fall short of 200. Of those emptying themselves into the Pacific, 
the San Juan, Churchunque, Bayano, Rio grande de Nata, Santamaria, 
Tavasarà, and Chiriqui are the largest: among those flowing into the 
Atlantic Ocean are the Chagres, Belen, Veraguas, and the nine-mouthed 
Atrato. Most of them have one or more deltas, which in many in- 
stances assume the appearance of islands. Their vegetation is a 
curious mixture of littoral and inland plants, and it often presents 
species of the higher mountains, by which the remote sources of the 
river may be traced, — LL. 
As the Isthmus connects the continents, so does its vegetation - 
combine the floras of tropical North and South America: the virgin 
forests of Guayana, the Vegetable Soory groves of the Magdalena, and — 
the oak-woods of the Mexican highlands, are all equally represented. — 
It is, therefore, not to be expected that the Panamian flora should — 
exhibit any very striking character, or be distinguished by the presence 
of strongly delineated forms, like Mexico by its Cactuses, Australia by © 
its Epacrideæ, capsular Myríacee, and phyllodineous Acacias, or the Cape - 
of Good Hope by its Heaths, succulent Aloes, Slapelias, and Mesem- — ; 
