en ai ne a Tee 
Rhine, Holland, and Belgium. 
NATURE 
447 
tion of valleys in this gravel or silt, and the production of such 
heights as those which bound such plateaux as Rivoli. 
4. Considerable local alterations in the relative level of land 
and sea along the west Neapolitan coast. 
5. The formation of the straits of Gibraltar. 
6. The excavation of such valleys as that of the Manganores 
in Central Spain, the formation of gravels containing flint imple- 
ments and mammalian bones near Madrid, and therefore far 
beyond the influence of marine action. 
7._ The wearing down of many of the valleys to the north of 
the Pyrenees below. the level of such lower mammaliferous caves 
as those in the neighbourhood of Tarascon; the dispersion of the 
results of the wear and tear of the second extension of the 
Pyrenean glaciers, and the filling up of the old valleys with it; 
the re-excavation of the valleys, and the carrying down of their 
silt or loess to the plains; the formation of streams and water- 
_ courses through this deposit. 
8. The formation of certain valleys in the Perigord by streams 
to a certain extent, but principally by the gradual effects of rain, 
heat, frost, and other meteorological actions. 
9. The excavation of the valleys of North and Eastern France, 
and the denudation and retrogression of their watersheds. 
to. The dispersion of Alpine rocks, gravels, and rocks to the 
north of the Alps, produced by the wear and tear of the great 
glacialisation, which was, in a general sense, contemporaneous 
with the first extension of the glaciers south of the Alps, and 
the first extension of the Pyrenean glaciers, occurred before man 
appeared in Europe. After his first wanderings and huntings he 
left his remains aboye this old Alpine detritus. Then the 
valleys in the carboniferous limestone of Belgium were worn 
down ninety yards or more by rain and rivers, and the bones of 
the extinct mammalia and rude stone implements and bones of 
“man were washed into caves with the gravel. 
After the retirement of the glaciers, subsequent to this second 
extension, the wash-down of the Alps, Vosges, and Ardennes 
was spread over the older gravel. It filled up the valleys, and 
extended with a thickness varying from a few yards to a thousand 
feet and more, all down and over what is now the valley of the 
The loess thus formed was then 
washed out of the valleys, was cut into by rivers, and has been 
worn down ever since. 
11. The separation of the coasts of France and England about 
Dover and Calais. 
12. The excavation of nearly all the valleys in the district east 
ofa line drawn from King’s Lynn to Portland, the denudation of 
- their watersheds, and retrogression of the river sources. 
13. The denudation of the valley of the Weald of Kent. 
14. The separation of the Isle of Wight frem the main land. 
15. The formation of a great part of the Bristol Channel. 
16. The upheaval of many sea beaches, and the general de- 
struction of forest land on the south and west of England ; the 
formation of many peats. 
17. Enormous destruction of the sea coast. 
18. A sufficient upheaval of the Scandinavian peninsula and 
Denmark, to produce such a restriction of the outlet as has 
determined a change in the marine fauna of the Baltic. 
19. A slow upheaval of large areas appears to have accom- 
panied the excavation of the valleys upon them, and a subsi- 
* dence of equally large districts appears to have accompanied the 
~ retical opinions are of no value whatever. 
recession of the second glaciers ; 
followed, ’ > 
20. The uprise of the Desert of Sahara in Africa after the 
second extension of the Alpine glaciers. 
probably another upheaval 
Secrion E.—GEOGRAPHICAL SCIENCE 
On Alinospheric Currents.--Mr. J, K. Laughton. In exanin- 
ing into the geographical distribution of winds, we must bexr 
in mind that well-attested and careful observation is tle 
only satisfactory basis, and that descriptions founded on theo- 
If we refer Had- 
ley’s Theory of the Trade Winds to this test, we find, i the first 
place, that the effect of heat in producing wind is not quite such as 
has been represented. Experimentally, heat does not produce a 
blast, unless the space between the heat and cold air be very con- 
~ fined, as is roughly shown by holding a newspaper before the 
fire. Geographically, heat does not cause a wind towards any 
of the principal areas of greatest temperature ; either towards 
the Great African Desert, the Desert of Arabia, or of Australia, 
towards the Red Sea or the Persian Gulf, or even, when care- 
fully traced, towards the Great Prairie of North America. Zy 
the second place, we find that the effect attributed to the rotation 
of the earth is not consistent with numerous observed facts, 
such as the S.E. wind in the Gulf of Mexico, the N.W. wind 
on the coast of North Africa, the N.W. gales in the North 
Atlantic, the S.W. wind on the south coast of Australia, and 
very many others ; and, indeed, the idea appears to have origi- 
nated in a temporary forgetfulness of the power of friction, 
which in the case of air and all fluids is very intense. 
Winds, which, in accordance with Hadley’s theory, have been 
very generally divided into folar and eguatorial, seem more 
naturally to divide themselves into easterZy and westerly ; and it 
is this division which has, from the days of Columbus, been 
adopted by really practical men, to whom the winds were matters 
of fact, not of mere theory; but the trade-winds—having 
attracted early notice by their very great steadiness and regu- 
larity—haye always been considered as the direct manilestations 
of the first cause, whatever it might be, of the great atmospheric 
movements ; the westerly winds, which were not discovered till 
much later, having been considered as secondary an‘l compara- 
tively of little importance. But, as our experience grows larger, 
we learn that the westerly winds have an extent and a strength 
and a rude vigour incompatible with the idea of their secondary 
nature. Whether in the northern or southern hemisphere, they 
are exceedingly violent and boisterous ; and, without considering 
the Arctic and Antarctic regions, concerning which we have not 
sufficient evidence, they extend from 60° N. to 60°S., interrupted 
only by the trade-winds, which blow over an area large indeed, 
but small 7 comparison with that on which they mtrude. The 
trade-winds are also of very limited height, whiist above them 
the westerly winds blow as strongly as they do in the temperate 
zones, where they reach into the upper strata of the atmosphere 
as far as we have any knowledge. We are thus led towards the 
conclusion that the westerly winds are really the primary winds, 
far extending and boisterous ; whilst the quiet equable trade- 
winds—of very limited volume—are reflex streams of air caused 
by the impact of the great westerly winds on the continental 
barriers, whether against mountain ranges or the more sluggish 
air which lies over the land. The Atlantic Ucean affords 
us the most familiar illustrations of this; where we see the 
main j westerly stream dividing on about the parallel of 45° 
N., and twning north, as a south-westerly wind on our 
coasts, and the coast of Norway ; or south, as a north-west and 
northerly wind on the coast of Portugal, and a north-easterly on 
the coast of Africa ; whilst the rest of it forces its way onward, 
a westerly wind over Northern Europe and Asia, or a northerly 
deflection in the several basins of the Mediterranean. On the 
other hand, on the extreme west, the westerly wind continually 
dragging away the air from the eastern side of tne Rocky Moun- 
tains, causes such a tendency towards a vacuum, that the air from 
the south and north is induced towards it, and the wind over 
Western America rules from the south or north, according as the 
:eason throws the axial line of the temperate zone to the north 
or south of its mean position. Examining at great length into 
the various local winds and irregularities in the different parts of 
the world, we arrive at the conclusion that the whole atmosphere 
has a continued tendency to move from west to east, and does so 
more when it is not interrupted. The interruptions are of two 
kinds; one occasional and irregular, being caused by fluctuations 
in the hydrostatic condition of the air, the other permanent or 
seasonal and regular, caused by the pressure of lines of coast and 
mountain ranges. 
It is impossible to say definitely why the atmosphere should 
have this prevailing motion ; but if the cause is neither heat nor 
the influence of the earth’s rotation, nor any agency which we 
can detect at work on the earth, we are driven almost insensibly 
to the belief that it must be the result of celestial attraction ; and 
the fact that the barometer shows no trace of any noteworthy rise 
or fall, as of am atmospheric tide, suggests that the atmospheric 
currents, which must necessarily be formed by the action of such 
an intense disturbing force, do not in any way clash, but flow 
uninterruptedly onwards in one certain direction, either towards 
the east or towards the west. All observation shows us that 
there is not a permanent current towards the west, but that there 
is one towards the east; and although we are unable at present 
to master all tle details of the manner of the motion, the evidence 
of geographical fact, combined with that of astronomical possi- 
bility, justifies us in inclining towards the belief that the motive 
force for which we are seeking is really the disturbing force of 
the attraction of the heavenly bodies, 
