684 THE POPULAR SCIENCE MONTHLY. 



THE BIKTH, LIFE, AND DEATH OF A STOEM.* 



By EOBERT H. SCOTT, M.A., F.K.S., Etc. 



WHEN we are asked to give an account of the birth of a storm, 

 we are reluctantly compelled to admit that our storms are, al- 

 most without exception, foundlings, and that, as the precise conditions 

 to which they owe their origin are, for the most part, shrouded in un- 

 certainty, warm discussions at times arise as to the parish whence they 

 have set out on their wanderings. 



Dove said long ago that storms were due to the interference of the 

 polar current or the east wind with the equatorial current or west 

 wind. He gave the winds these names, because on his views the east 

 winds really consisted of air flowing from the north or south pole 

 toward the equator, which was modified in the direction of its motion 

 by its change of latitude ; while west winds were really due to air en- 

 deavoring to make its way back to the pole from the equator, whose 

 coarse was in its turn modified by its moving from lower to higher 

 latitudes. To the conflict of these two grand currents, east and west 

 winds, Dove attributed all our storms ; but he did not attempt to ex- 

 plain how the currents came into collision. 



These views, however correct on their cosmical principles, have 

 been superseded, of late years at least, as regards the explanation of 

 our winds, by the modern views of the relation between the wind and 

 the distribution of barometrical pressure ; but, unfortunately, we still 

 remain in comparative ignorance of the ultimate causes to which this 

 distribution of pressure, or the rise and fall of the barometer, are due. 

 To give some conception of the existing difference of opinion on these 

 fundamental principles of our science, I may say that while some au- 

 thorities maintain that the force of the wind in a hurricane is caused 

 by the amount of barometrical disturbance which accompanies it, 

 others hold that the fall of the barometer at the center is itself, in 

 great measure, due to the centrifugal force of the revolving mass of 

 air. 



Of the various theories which have been propounded to account for 

 storms, which are generally more or less cyclonic in their character, I 

 shall only mention four : 



1. Some authorities, and among them our own countryman the 

 Rev. Clement Ley, attribute the formation and subsequent progress 

 of a storm to the condensation of moisture, but they apparently ignore 

 the fact that many of our very heaviest rains do not give rise to cy- 

 clonic disturbances of serious character. For instance, when on April 

 10 and 11, 1878, 4 - 6 inches of rain fell at Haverstock Hill, we had no 



* Founded on a lecture delivered by the author at the London Institution, February 

 3, 1879. 



