72 REPORT—1846. 
Along the watershed, that is to say at the extreme eastern edge of the table-land, 
several lakes of some magnitude are situate, namely, A’shangi, Haik and Zuwai; 
and the great lake Zambézi, or Nyassi, lying further to the south, would appear to 
be, in like manner, placed near the line along which the minor streams falling 
into the Indian ocean are divided from those of larger size which flow towards the 
Atlantic. 
The memoir concludes with directing attention to an important practical result 
which is to be arrived at from this brief survey of the physical character of the 
Abessinian plateau. ‘It is, namely, that the eastern coast of Africa presents 
facilities for the exploration of the interior of that continent very superior to those 
afforded by the western coast. For, when the narrow belt of low land along the 
coast of the Indian Ocean—which from its general dryness, arising from the 
absence of large rivers, is far from unhealthy at most seasons of the year—is once 
passed and the eastern edge of the elevated table-land is attained, a climate is met 
_with which is not merely congenial to European constitutions, but is absolutely 
more healthy than that of most countries. Here—that is to say, on the elevated 
plateau, and not in the low desert country along the sea-coast—travellers might wait 
in safety, and even with advantage to their health, till suitable opportunities should 
present themselves for penetrating westward into the interior; and in the event of 
their having to retrace their steps, they would only return upon a healthy and de- 
lightful country. On the other hand, the climate of the western coast is notoriously 
such, that a traveller is necessitated to press forwards, whatever may be the time of 
the year, whatever the condition of the country, whatever even his state of health. 
And should he, from sickness or any other unforeseen circumstance, be compelled 
to abandon his journey, he must do so with the painful knowledge that the further 
he retrogrades the more baleful are the districts which he has to traverse and the 
less likelihood there is of his ever reaching the coast.” j 
Synopsis of a proposal respecting a Physico-Geographical Survey of the British 
Islands, particularly in relation to Agriculture. By W. DesBoroucH 
Coorey, Esq. Communicated by Sir R. I. Murcuison, G.C.S., F.R.S. 
1. Physical geography, or that branch of knowledge which treats of natural 
phenomena and their laws collectively, as they are modified by geographical position, 
furnishes some of the chief elements of agricultural science. It teaches the rela- 
tions of comparative climate, without a knowledge of which the results of local 
experience cannot be safely applied to any extent in agriculture. 
2. It is well known that as climate depends fundamentally on the distribution of 
land and water, on the winds, and is affected probably by other influences not so 
easily recognised, its changes and gradations deviate widely from the simple rules 
deducible from geographical position. The lines marking certain degrees of mean 
temperature, of summer heat and of extreme cold, do not run in parallels of lati- 
tude ; nor are they parallel to one another, but diverge as we proceed from W. to E. 
3. The lines above described, and which are denominated respectively Isothermal, 
Isotheral and Isocheimal, are, notwithstanding their apparent irregularity, the 
fixed boundaries of very interesting natural domains ; for they mark out the several 
zones of vegetable life, and the regions suited to the cultivation of different kinds 
of plants. 
i To the determination of these lines may be added observations of some other 
phenomena which also contribute to ascertain the conditions of vegetation ; as rain, 
its quantity at different seasons ; humidity without rain ; the temperature of the 
earth ; its form, conducting and radiating properties, &c. 
5. A knowledge of these particulars can only be derived from observations in 
sufficient number systematically made, and referable to a common standard. 
6. The phenomena of physical geography may be considered as determined in a 
general way for the north ot Europe (Denmark), and for the south of Europe also 
(Italy), by Schouw ; and for eastern Europe (Russia) by Baer and Kupffer. For 
western Europe, or the British Islands, numerous observations of this kind are in- 
deed on record ; yet they still want completeness, minuteness, and uniformity ; nor 
has any attempt been made to arrange them systematically with a view to popular 
use. 
