418 The Origin of the Great Cyclones. (October, 
Wellington’s strategy in forming the famous lines of Torres 
Vedras. 
The only theory for the generation of cyclonic storms 
which has engaged more than an ephemeral existence is 
that of M. Dové, the distinguished meteorologist of Germany. 
Taking the West Indian cyclone as the type of all others, 
beginning in the intra-tropical regions and extending into 
high latitudes, M. Dové is the well-known advocate of the 
doctrine that these storms ‘‘ Owe their origin to the intrusion 
of the upper counter trade-wind into the lower trade-wind 
current.”* Without now entering into a discussion of this 
hypothesis, it will be proper for me to mention a different 
one advanced some time ago by myself, as a substitute for 
the older one of Dové, and as affording a satisfactory 
solution of all tropical storms and cyclones. This hypothesis, 
which will here be fully stated, was also based on the 
agency of the trade-winds, but in a manner totally distinéct 
from that assumed by the German meteorologist ; and in 
the original statement of my own views it is asserted that 
“‘the origin of cyclones is found in the tendency of the 
South-East trade-winds to invade the territory of the North- 
East trades, by sweeping over the Equator into our 
hemisphere, the lateral conflict of currents giving an initial 
impulse to bodies of air, by which they begin to rotate.” 
This explanation will take us aside for a while to notice the 
law of storms and the region of the trade-winds, upon 
which, according to the two hypotheses, the tropical storm 
has its birth. 
It can hardly be necessary in stating the law of storms, 
as first announced and established by Mr. Redfield, to do 
more than call attention to its fundamental condition. In 
Europe, meteorology has made rapid strides. Since the 
institution of the Weather Bureau in the United States, 
the eye of every American has become familiar with the 
daily isobaric and other isometeoric lines on the weather 
maps of the War Department, displaying with the fidelity 
of an automatic instrument a tri-daily photograph of the 
never quiet aérial ocean. He has learned to watch its 
mighty pulsations. He traces from day to day the exactly 
delineated area of every passing storm, and follows its 
cloud-led march from shore to shore of the Continent. 
Nothing of importance in the meteoric world in his own 
country can escape him, for he is in telegraphic communi- 
cation with every part and corner of its vast territory. 
* Dove’s Law of Storms, p. 264. 
