402 ALEXANDER BUCHAN ON THE 
N. W. Provinces, where rain falls all the year round, 0°088 and 0075 inch. 
Again, at Aden, Arabia, where the weather of summer is peculiarly hot 
and dry, while the winter oscillation is 0°109 inch, that of summer rises to 
0°142 inch. The point to be insisted on here is that whatever be the cause or 
causes to which the daily oscillation is due, the absolute amount at particular 
places is largely dependent on comparatively local causes ; numerous illustra- 
tions of which, in addition to the above, may be adduced from many other 
parts of the earth, showing the influence in the same direction of prevailing dry 
or wet, and hot or cold seasons on the amplitude of the oscillation. But the 
most striking illustration occurs over Southern Asia, where, on comparing the 
July with the January chart, the space shaded for 0100 inch and upwards all but 
disappears from this extensive region during the season of the summer monsoon. 
The lines of 0:080 inch appear to pass round the globe in December, 
January, March, and April, but not in the other months. The lines of 0-060 
inch, and those indicating a smaller oscillation, pass round the globe at all 
seasons. It will also be seen that the lines taken as a whole attain their 
greatest degree of parallelism with the lines of latitude in January, and that on 
the other hand they are most distorted in July, particularly as regards the lines 
of smallest amplitude of oscillation. 
The amount of the oscillation at places immediately bordering on the 
Mediterranean Sea is greatest during the winter months. In April, when the 
temperature is rising very rapidly, the amount is diminished, and a small 
patch to the west and the south of Italy begins to be formed, over which the — 
oscillation does not amount to 0°020 inch. In May this area of small oscillation 
is greatly extended south and south-eastwards, and in June still further, in 
which month the maximum extent of this well-marked and annually recurring 
diminished diurnal range is reached ; in July it is much reduced in area, and in 
August it has almost disappeared, being now apparently limited to Sicily and 
the extreme south of Italy. 
A state of things, the reverse of the above, obtains over the extended 
peninsula of the south-west of Europe, lying between the Mediterranean Sea 
on the one hand, and the Atlantic, North, and Baltic Seas on the other, includ- 
ing thus the inland districts of the Spanish Peninsula, France, Switzerland, 
Germany, and Austria. Of this extended peninsula, the part most completely 
enveloped by the ocean is Spain and Portugal, and here it will be observed that 
the amount of the oscillation is greatest, and that it begins markedly to rise in 
March. On the other hand, in Germany and Austria, where the breadth of the 
land is greatest, and where the peninsula blends with the Europeo-Asiatic Con- 
tinent, the amount of the oscillation is least ; whereas, in France, the amount is 
intermediate between that of Spain and that of Germany. This maximum 
oscillation during the warmer months of the year may be studied on the maps 

