22 On the Action of the Barometer in a Hurricane, etc. 
movements of the earth’s surface; he says that their earliest ac- 
tivity and violence may be explained by 2 — of local cur- 
rents; that opposite winds may coalesce in a vast gyration, in- 
stead of following ae usual stratiform course magi interfer- 
ence with each other: and that when once the fall of the barom- 
eter and the involute vortical movement has been established, 
the extraneous and tangential forces of Ales cue winds is not 
necessary to continue the action; for the law of centrifugal action 
must produce an accumulation of pressure beyond the active 
verge of the whirlwind, and the pressure of the external atmos- 
phere alone, around the basin of the storm, constantly keeps up 
the involute vertical movement, and is sufficient to maintain the 
existing vortical action. 
those who entertain this idea, to view it in connec- 
tion with the conditions that existed in the valley of the Ohio on 
the afternoon of ae 80th, particularly in the vicinity of New 
atic Granting that the circumstances described by Mr. 
Redfield did pacar a cyclone or rotary storm, is the cause he 
has assigned, consisting of the mere mechanical force of ——— 
sufficient to impel a rotating disk of atmosphere of some 30 mi 
in diameter, as in the tornado in question, many hundreds of 
miles, which disk had carried with it, and still maintained, as it 
entered the valley of the Ohio, a power that could prostrate 
thousands of trees on successive miles in successive eer 
which swept off houses, and carried cattle up far in the 
To me the thing is inconceivable, the cause is not. adeyuate 
to the effects ; and it e more inconceivable when it is known 
that, in this, as in ae ance of the kind, the destructive action 
was tniermitient, that some parts of the track were passed over 
without destruction, and that in others it was exerted with vari- 
ous degrees of violence. This spasmodic action is not in accord- 
ance with the inherent mechanical force ascribed to the cyclone; 
and some other cause is requisite for the production of these ef- 
fects of this now retarded, and now accelerated, mechanical {ope 
But Mr. Redfield says that it is not requisite ; ‘extraneous aid, he 
says, is not necessary to keep up the vortical action, for when once 
the fall of the barometer and the involute vortical motion has 
been established, the law of centrifugal action must produce an 
accumulation of pressure beyond the active verge of the whirl- 
wind, and this ure alone, around the basin of the storm 
must keep up the involute v ortical action. But, as experience 
shows in the New Harmony tornado, in opposition to Mr. Red- 
field’s theory, there was not any diminution of pressure near 
writer ere mistaken the views of Mr. Redfield, who makes the move- 
sok of the eyclone over the earth’s surface in no sense a consequence of the rota- 
tion: an shown arte jon is a necessary 
when the axis of the cyclone ito vera Ee secon 
