146 
THE COUESE OF STOEMS. 
The length of course varies greatly. Some have a very short 
life. Others retain their identity through a course of many 
thousands of miles. One originating on the Pacific coast of 
America traverses the entire American continent, and tbe 
Atlantic Ocean. 
Lastly, the rate at which these centres move is hy no means 
uniform. In the chart we find eight to twelve days occupied in 
crossiug the Atlantic. From other sources there is reason to 
believe, that the time occupied may range from three to sixteen 
or even twenty days. 
A number of interesting questions are suggested by a chart 
of this kind. 
What determines, in the first instance, the formation of a 
centre of depression with winds circulating round it ? 
What is the causal relation between the depression and the 
wind ? Does the wind cause the barometer to fall, or does the 
fall of the barometer produce the wind ? 
Why should storms once formed move from West to East, 
rather than from East to West ? 
Why in particular instances should they change their 
direction or become stationary ? 
Why should some fly across the ocean with the speed of an 
express train, while others, not less energetic as regards their 
internal movements, creep and loiter in their course ? 
Lastly, what light does the chart throw upon the vexed 
question of the possibility of predicting European storms from 
the American side of the Atlantic ? 
I pass over all these inquiries hut the last. On that I have 
a word to say. 
It is well known that some few years ago, the enterprising 
proprietor of the New York Herald instituted a system of storm- 
warnings, despatched hy telegraph from New York to London, 
and published in the daily newspapers throughout this country. 
