130 Additional Objections to Redjield's Theory of Storms. 



higher, or if elastic, denser at an intermediate point than the 

 general level. In the case of an elastic fluid like the air, con- 

 densation will be substituted for accumulation, and will amount 

 to the same thing in effect. It would follow, that as the whirl 

 should advance, the barometer would rise until the front limb of 

 the zone of greatest condensation should arrive: subsequently it 

 would fall till the central space should arrive, and then another 

 rise and subsequent fall would ensue during the approach and 

 departure of the rear limb of the zone of greatest condensation. 



61. One fact is mentioned among the contradictory evidence 

 above quoted, which seems to be supported by universal experi- 

 ence. The barometrical column does fall at the commencement 

 of a storm, and of course this fact does not accord with the idea 

 that storms are whirlwinds produced by mechanical forces remote 

 from the axis and attended necessarily by a centrifugal action 

 which would accumulate the air towards the exterior. 



62. Respecting another characteristic, the '■^ reliable facts and 

 observations of our theorist,''^ are no less irreconcilable than in the 

 case last considered, I allude to the changes in the direction of 

 the wind which ensue from the commencement to the end of a 

 hurricane, and especially on the outer limbs on each side of the 

 line of progression. 



63. Thus speaking of the progress of a storm from southwest 

 to northeast along the coast of the United States, he alleges that 

 ^^ along the central portions of the track the first force of the witid 

 is from a point near southeast, but after blowing for a certain pe- 

 riod it changes suddenly, and usually, afte]||a short inter- 

 mission, to a point nearly or directly opposite to that from which 

 it has previously been blowing ; from which opposite quarter it 

 blows with equal violence till the storm has passed over or aba- 

 ted.''^ Again, " It is demonstrably evident, that at any point over 

 which the centre of a whirlwind may pass, the wind must sud- 

 denly chatige to a direction almost exactly opposite to that lohich 

 has bee7i felt during the preceding part of its progress.^' (This 

 Journal, Vol. xx, p. 22.) " /^ sometimes happe?is when the cen- 

 tral portion of an extensive storm passes over or near the point 

 of observation that the comparative calm or lull which prevails 

 about the apparent centre of rotation, is preceded hj a gradual 

 rather than a sudden abatement of the wind. ^^ Every experi- 

 enced navigator will shrink with instinctive apprehe?ision from 



