1822.] 
chain, the perpetual snow does not 
come down as low as might be expected 
from the latitude. Another objection 
is, that plants vegetate there at an ele- 
vation where they would grow no where 
else, and to this is added, that the re- 
fraction may be taken for soniething in 
those calculations. 
M. de Humboldt has made observa- 
tions to shew, that to bring down these 
mountains to the level of the Chimbo- 
rasso, we must suppose the co-efficient . 
of the refraction to 0,3 instead of 0,08, 
a quantity inadmissable in so southerly 
a zone. It is very true, that in the 
passages, and at the back of the Hima- 
Jaya, abutting the plains of Tartary, 
‘the snow melts in summer at the height 
of 5,077 metres; a height where under 
the Equator itself, it is doubtless eter- 
nal. Mr. Webb found none at 300 
feet still higher, although he made his 
observations at the 3lst degree of N. 
latitude. In that very latitude, north 
of the crest of the Himalaya, are found 
pastures, wheat, and excellent vegeta- 
tion, at the height of 4549 metres, while 
on the southern point of these same 
mountains, the phenomena are little 
different from what has been observed 
in other countries of the globe. 
M. Humboldt remarks on this sub- 
ject, that the limits of perpetual snow, 
form one of the most complicated re- 
sults of physical causes; that they are 
not so much regulated by isothern 
lines (or of a medium and equal heat 
during the year) as by isotheres, or of 
equal extreme heat in summer; and 
that these two kinds of lines are far 
from being parallel. It is also ad- 
mitted that in the interior of large 
continents, the annual heat, and espe- 
cially the summer heat, in equal lati- 
tudes, become stronger than on the 
eoasts, by reason of the sun’s radiations. 
We may conceive then that on moun- 
tains, whose backs incline towards 
large plains, perpetnal snow may be 
more retired and nearer the heights; 
indeed similar effects are witnessed on 
the chain of Caucasus. 
M. Humboldt analyses and appre- 
eiates several other causes that may 
~ contribute to the above variations, and 
introduces some observations made by 
him on the subject, in different parts 
of America. 
SCIENTIFIC LABOURS of M. DE LA- 
LANDE in the COUNTRY of the HOT- 
. TENTOTS and CAFFRARIA. 
- ‘THE Cape of Good Hope occupied for 
MontTuuy MAG. No, 365, 
Institute of France. 
145 
a length of time by Europeans, was 
thought to have been sufficiently ex- 
plored, but thecollections brought from 
thence by M. de Lalande lead to an 
inference very different. By his instru- 
mentality, we are made far better ac- 
quainted, if not with the soils, at least, 
with the productions of Austral Africa 
in plants, animals, and other organized 
beings. 
This voyager had already exhibited 
proofs of his zeal and capacity, m three 
voyages undertaken for the government 
at Lisbon, to the coast of Provence and 
to Brazil, Accompanied by a nephew 
only twelve years of age, who shared 
all his fatigues and labours, M. de La- 
lande, quitted Paris on the 2d of April, 
1818, and on the third of August follow- 
ing, had arrived at the anchorage off 
the Cape. After several excursions and 
discoveries in the vicinity of Cape 
Town, he entered the country of the 
Hottentots, on the 11th of November, 
1818. On his return, he advanced to 
the provinceof Birg River, July 5, 1819. 
and on the 2d of November following, 
he set out for Caffraria. 
With. no other attendance than his 
nephew and a few ignorant Hottentots 
or Negroes, it took some time before 
M. de Lalande could proceed in his re- 
searches, at the distance of 800 miles 
from the chief seat of the colony. He 
was insulated, as it were, in a western 
territory, at a time when the Caffres 
were very hostile to the Europeans 5 
but this circumstance, though a perilous 
one, could not frustrate the accomplish- 
ment of his mission. 
It was only at that distance that he 
could expect to find an enormous qua- 
druped, the two horned rhinoceros, an 
object he was very anxious to obtain, 
He maintained his ground in that in- 
hospitable region, till he discovered 
and laid prostrate that prodigious ani- 
mal, twelve feet in length, which had 
long been a desideratum in our collec- 
tions and works of natural history. 
This fortunate acquisition was made in 
a territory west of the Cape. 
Sometime after, he turned, in an 
easterly direction, in quest of another 
prize which had been recommended to 
him. The skeleton of an animal not 
less colossal must be also secured, as es- 
sential to thé requirements of science. 
At Birg River, he commences the pur- 
suit of the hippopotamus ; he comes up 
to a whole family of them, kills their 
chief, the largest and most formidable. 
A colonial law prohibited the pally oe 
the 
