S78 Baron Humbpjdt ow the- Laws which are observed 
Australis^ vol. ii. p. 538; and Observations systematic and 
geographical wi the Herbaries of the Congo, p. 3.) I made 
an attempt, in J 815, to pursue this kind of research, in e^fpnd- 
ing it to the different orders or natural families. The natural 
history of the globe is, in its numerical elements, like the sys- 
tem of the world, and can be brought to perfection only by the 
joint efforts of botanical travellers, to discover the true laws of 
the distribution of vegetables. The collection of facts is not of 
itself sufficient : in or4er to obtain the most accurate apppxi- 
mations, (and we do not pretend to give any thing but approxi- 
mations,) the different circumstances under which the observa- 
tions have been made must be discussed. I think with Mr 
Brown, that we ought to prefer in general to calculations made 
upon incomplete lists of all the plants published, the examples 
taken from countries of considerable extent, and wjiose J'lofa is 
well known, such as France, England, Germany, and Lapland. 
It would be desirable to have still a complete Flora of two coun- 
tries of 20,000 square leagues, destitute of lofty mountains qnd 
of platforms, and situated between the tropics in the Old and ip 
the New Worlds. Until this shall be accomplished, we must be 
contented with the great herbaries formed by travellers, who 
have resided for some time in the two hemispheres. The habi- 
tations of plants are so ^vaguely and incorrectly pointed out, in 
the vast compilations known under the names of Systema Vege^ 
tabilmm, 9^nd Species PJantarum, that it would be very dange- 
rous to use them in an absolute manner. I have not employed 
these lists otherwise than in a subsidiary manner, to control 
and modify a little the , results obtained by the Floras and the 
partial herbaries. The number of equinoctial plants which M. 
Bonpland and I have brought to Europe, and of which our 
learned colleague M. Kunth will have soon finished the publi- 
cation, is perhaps numerically greater than any of the herbaries 
formed between the tropics ; but it is composed of the vegetables 
of the plains and elevated platforms of the Andes. The al- 
pine plants are even much more considerable than in the Floras 
of France, of England, and of the Indies, which associate also 
the productions of different climates belonging to the same lati- 
tude. In France, the number of species which vegetate exclu- 
sively at above 500 toises of height, does not appear to be more 
