GEO YE OE PALM-TEEES. 
421 
brambles* remind us of the form of our European vege- 
tation. We in vain hoped to find on the mountains of 
Caracas, and subsequently on the back of the Andes, an 
eglantine near these brambles. We did not find one in- 
digenous rose-tree in all South America, notwithstanding 
the analogy existing between the climates of the high 
mountains of the torrid zone and the climate of our tem- 
perate zone. It appears that this charming shrub is want- 
ing in all the southern hemisphere, within and beyond the 
tropics. It was only on the Mexican mountains that we 
were fortunate enough to discover, in the nineteenth degree 
of latitude, American eglantines.! 
We were sometimes so enveloped in mist, that we could 
not, without difficulty, find our way. At this height there 
is no path, and we were obliged to climb with our hands 
when our feet failed us, on the steep and slippery acclivity. 
A vein filled with porcelain-clay attracted our attention. J 
It is of snowy whiteness, and is no doubt the remains of 
a decomposed feldspar. I forwarded a considerable portion 
of it to the intendant of the province. In a country where 
fuel is not scarce, a mixture of refractory earths may be 
useful, to improve the earthenware, and even the bricks. 
Every time that the clouds surrounded us, the thermometer 
sunk as low as 12° (to 9't>° It.) ; with a serene sky it rose 
to 21°. These observations were made in the shade. But 
it is difficult, on such rapid declivities, covered with a dry, 
shining, yellow turf, to avoid the effects of radiant heat. 
We were at nine hundred and forty toises of elevation; and 
yet at the same height, towards the east, we perceived in a 
ravine, not merely a few solitary palm-trees, but a whole 
grove. It was the palrna real ; probably a species of the 
genus Oreodoxa. This group of palms, at so considerable 
* Rubus jamaicensis. 
f M. Redouts, in his superb work on rose-trees, has given oar 
Mexican eglantine, under the name of Rosier tie Montezuma , Montezunaa 
rose. 
t The breadth of the vein is three feet. This porcelain-clay, when 
moistened, readily absorbs oxygen from the atmosphere. 1 found, at 
Caracas, tile residual nitrogen very slightly mingled with carbonic acid, 
though the experiment was made in phials with ground-gkes stopper 
«iot filled with water. 
