﻿430 Mr. J. K. Laughton on Barometric Differences 



can alone make ns satisfactorily acquainted with. Independent 

 of the great weight due to Admiral Fitzroy's opinion, there are 

 many considerations which appear to sanction this view to the 

 fullest extent, and to render it imperative that a correct know- 

 ledge of the seasons, the directions, and the characteristics of the 

 prevailing winds in the different parts of the world should form 

 the basis of any inquiry into the origin of storms : it is their ex- 

 ceptional nature which has to be inquired into ; and the regular 

 course to which they are exceptions must first be clearly under- 

 stood. Meteorologists have, as a body, ignored this necessity, 

 and, in treating of storms, have affected to consider the air as in 

 a state of rest, and disturbed from that state by the sudden de- 

 velopment of some agency which destroys the hydrostatic equi- 

 librium. But, in point of fact, the normal condition of the air 

 is not one of hydrostatic equilibrium : in almost every part of 

 the world, and at every season, some particular wind has a de- 

 cided predominance over every other; and wherever storms 

 occur, they follow the course of the prevailing wind of the loca- 

 lity and season. The exceptions to this rule are extremely rare ; 

 and admitting that storms are most commonly of the nature of 

 cyclones, I can see in the law which directs their track no dif- 

 ference from that which directs the onward motion of the angry 

 eddies which form in a rapid stream. And in the same way as 

 such whirls generally form in particular places, where we can 

 often point out the cause of the irregularity (as, for instance, 

 where another stream shoots in its waters across the course of 

 the main current, or where a boulder or some partial obstruction 

 breaks the evenness of the flow), so also do storms form most 

 frequently in special localities, in almost every one of which we 

 can point distinctly to the near approach of intrusive currents, 

 or to the headlands, islands, and opposing shores round and 

 against which the wind fumes and rages. Whether we consider 

 the tropical Hurricanes (taking their rise on the equatorial mar- 

 gin of the Trade-Winds or in the conflict of changing Monsoons), 

 the storms of the North Atlantic (where the northerly gales from 

 the coasts of Greenland are driven into the body of the west 

 wind), the storms off Cape Horn or the Cape of Good Hope 

 (the Cape of Storms), or even those off Cape de Gata, or Cape Ma- 

 tapan (famous in story), off Bermuda with its countless number 

 of islands, or the Abrolhos, or the Low Archipelago, or in any 

 other locality where storms are notoriously frequent and violent, 

 — we find everywhere, or with very few exceptions, some marked 

 feature, either of the prevailing wind in the stormy season, or in 

 the geographical peculiarities of the land, which seems directly to 

 associate itself with the irregularities in the aerial current. 



It is this geographical distribution which leads me forcibly to 



