June 14, 1858.] 
ADDITIONAL NOTICES. 
369 
an ascending current which in those parts rises nearer to the coast-line than 
to the massive and terraced heights of the centre; the breezes are thus hin- 
dered from penetrating into the interior, and it doubtless thence happens that 
the pine-woods approach the sea more nearly in the south-east part of the 
island, whilst in the south-west they are withdrawn into more central posi- 
tions. On the two sides of Fajaa d’Ovelha, which rise almost perpendicularly 
from the sea-shore, the groups of pines are favoured by winds coming in a 
direction given to them by the ascending currents from the neighbouring 
ribeiras ; whilst above Prazeres and Arco da Calheta these trees are mostly 
limited to the crests of the heights, the smooth slopes of which cause the 
ascending current to be driven farther into the interior. The south coast is 
especially suitable for observations on the regular changes of the land and sea- 
breezes. The northern coast affords less facilities for them on account of its 
humidity and dense vegetation. Thermometric observations made in the 
neighbourhood of Funchal (at Caminho de Torrinha, 284 feet above the sea) 
have proved that the temperature of the air is generally at its maximum 
towards noon ; the latter may, however, be attained before that time, on days 
when the morning has been cloudy. If in the forenoon the sun dispels the 
clouds, the maximum is reached more than an hour before noon, since the 
sea-breeze adds to its intensity. 
The impression made by the first sight of Madeira on an inhabitant of the 
Alps has been mentioned. Some comparisons may therefore be made between 
the slopes of the valleys in the two regions. The sources (of the rivers) in 
Madeira cannot be regarded in the same point of view as those in the Alps, 
where the water gushes from the rocks, or issues from beneath glaciers. In 
those mountains are seen furrows of rapid descent which conduct the condensed 
moisture into a common bed. Nevertheless the ribeiras of Madeira, to a cer- 
tain extent, bear a similarity to the upper courses of the rivers of the Alps. 
On account of the considerable elevation of the central mass of the island (the 
mean height of Madeira being, however, not more than about 2660 English feet 
above the sea), the loftiest summits are found almost immediately overlooking 
the deepest valleys, which, seen from commanding eminences, appear to have 
their floors almost horizontal. This is why it is sometimes heard said at 
Funchal, that “ the Ribeira dos Soccorides flows upwards from Curral to the 
sea, as is proved by the view of it from the summit of the Pico dos Bodes ! ” 
However, even an experienced eye may be deceived as to the actual propor- 
tions of descent of the ribeiras. The following table gives the absolute and 
relative fall of the four principal rivers of the island, taking as the commencing 
point of each the place of junction of mere brooks, the heights of which are 
indicated in the Map : — 
The R. dos Soccorides has an actual descent of 2086 ft., or 348 ft. per Eng. m. 
Brava 
11 
2170 
„ 460 
Janella 
11 
3200 
„ 533 
11 
do Porco 
11 
1200 
„ 600 
11 
These are descents which are never met with in the Alps, unless excep- 
tionally. 
The figures set down above, and the directions of the ribeiras, prove that 
the waters have found no great resistance to their flow from the volcanic for- 
mations, and that they pursue very nearly the shortest courses. If it be 
asked why it is not so in the Alps, it will be worth while to consider the 
nature of the declivities which make the greatest resistance, such as the rocks 
of the Alps oppose to the flow of the waters. The formations which oblige 
rivers to make the greatest windings are those of chalk ( Terrain cretace ), and 
the upper beds of the Jura formation. Examples in proof of this are seen— 
2 F 2 
