THE BIRTH, LIFE, AND DEATH OF A STORM. 249 
Such a diagram also shows us that it is quite a mistake to 
consider all east winds as dry ones, for in a cyclonic system the 
cloud area extends on the northern side, where the wind is 
easterly, nearly as much as on the southern, where the wind is 
from the westward. In fact, many of our wettest days occur 
with easterly winds, when one of these depressions passes to the 
south of the station where we may be. 
I shall now proceed to give a slight sketch of what we have 
learnt of the movement of storms. This, as far as we can see, 
is regulated by the position of the areas of high pressure, or, as 
they are called, the anticyclones. This is a term introduced 
about fifteen years ago by Mr. Francis Galton, to indicate an 
area of excess of pressure out from which the air is slowly whirling 
with a motion opposite to that which it has in cyclones. If we 
find an anticyclonic area existing over any region, we know that 
the cyclonic disturbances will skirt round it and develop their 
strongest wind on the side which lies closest to the district of 
high pressure. 
Thus if the anticyclone lies over France, the cyclonic distur- 
bances will move from west to east over the British Isles. If 
the area of high pressure lies over England, the depressions will 
sweep outside the Scotch coast, and reach Norway north of the 
60th parallel. If the anticyclone lies to the westward, and the 
pressure is higher in Ireland than in Great Britain, there is danger 
of northerly gales on the east coast of England, from cyclonic 
disturbances travelling southwards over the North Sea. 
In every case the cyclone moves with the prevailing wind 
along its track. 
Unfortunately we know very little about the rate at which 
these storms advance, some of them moving at the extraordinary 
speed of 50 or 60 miles an hour, as for instance, that of March 
12, 1877 ; while others, like the West India hurricanes/ do not 
attain one- fourth of that rapidity of translation. It is remark- 
able that the rate of progress bears no relation to the intensity 
of the storm, the slow moving tropical hurricanes being infinitely 
more violent than many of our rapidly moving disturbances : 
although the storm already mentioned in March, 1877, was 
severe enough, at least in the north of France, to satisfy any 
requirements. 
As regards the distance which storms have been known to 
travel, I may cite a very long-lived storm, which lasted nearly a 
fortnight in August, 1873, and which was traced along its course 
by my friend, Captain Toynbee, by means of the logs of 260 
ships which were in the Atlantic during its continuance. Its 
history will be found in the last published work of the Meteoro- 
logical Office, “ The Weather over the Atlantic Ocean during 
August, 1873.” This particular storm wrought immense 
