ADVERTISEMENT.

HER Majesty's ship Sulphur was the school in which I more particularly studied geographic botany. Preconceived views, and results drawn from the perusal of the writings of scientific travellers, were here practically tested. Her extensive voyage, and rapid transition from one portion of land to another, afforded rich and most favourable sources of comparison. With a bias towards the subject, it was an occupation of delight to develope the principles of the study, and to apply them to a result. Climate is the basis on which the earliest data must be founded, and with the liberal use of instruments, observations on temperature and humidity were in time collected. These, with observations on the physical condition of the surface, furnish us with many of the circumstances which govern the distribution of the flora of the world. What I have accomplished under these heads has been collected together, and form the subject of a lengthened paper, which, through the liberality of the proprietors of the Annals of Natural History, has been already published. Naturally following the consideration of physical agents, were the subjects of original distribution, amount, relative proportion to space, and similar details; but which I have not yet ventured to make public.

The result of these investigations was the developement of regions of vegetation, and which had their origin and stability in previously established views. At the same time, I do not insist that these are natural, but that taken in their entireness, they present in situations circumstances of remarkable individuality. In the meantime they will be found eminently useful in studying the features of vegetation, and more particularly in leading the subject to the naturalization of plants-the great end and aim of geographic botany.

My views respecting these regions have been more fully dwelt on in Sir W. J. Hooker's Journal of Botany for June 1842, and our space here does not permit me to enter on these at a greater length. It is enough to add that these regions are the results of observations matured during the voyage, and that with fourteen of them I have been practically acquainted.

R. B. H.

THE

REGIONS OF VEGETATION.

I. THE GREENLAND REGION.

EXTENT.-An important portion of the northern hemisphere is occupied by a vegetation entirely without trees, and covering a dreary, bleak, inhospitable surface, hardly capable, even in the most favoured spots, of any cultivation. Greenland composes much of this, and the region further comprises that part of America to the north of a line commencing at Hudson's Bay in 600 N. lat., thence stretching to 68° at the Mackenzie river, and continued to Behring's Straits; with that part of Siberia to the north of 65°, and Iceland, Spitzbergen, and Melville island. The natural course of this line is with the forest, obeying its sinuosities and sweeps, and will be found to enclose a region of some peculiarities. The northern limit of course only ceases with the vegetation.

PHYSICAL CHARACTERS.-The surface is usually extremely rocky and rugged, destitute of soil, and maintaining its flora in sheltered valleys and ravines. It is now a re