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Tornado in N. E. part of Ohio, Feb. 4, 1842. 283 
tance travelled estimated at three fourths of a mile, which isa 
velocity of fifty two miles per hour. According to the best tes- 
timony I could obtain, the tornado passed Chagrin River ata 
quarter past four; passed Painesville a quarter before five. Velo- 
‘city seventeen miles in thirty minutes, or thirty four miles per 
I have obtained an independent estimate of the velocity, in the 
following manner. The tornado accompanied the change of 
wind from south to west, which was experienced over a large 
territory. This change of wind was at Hudson cotemporaneous 
with the barometric minimum, and it is presumed to have ad- 
vanced with nearly the same velocity. Ihave therefore sought 
for barometric observations, and have obtained them for the four- 
teen following stations. The time of barometric minimum is 
not in all cases the time of the lowest observation, but is obtained 
by projecting the observations on paper and comparing the curves 
at the different stations. 
Time of minimum. - || on. Time of minimum. 
1842, Feb. 3,1 v.m.| Uniontown, Pa. |1842. Feb. 4, 7 P.m. 
. 4,2 a.m.| Gettysburgh, Pa - pee © ae 
«  & 0% p, w.| Rochester, N. Y € 5 lam 
‘e “4 | w York Cit “ce eerie. $6 
“ G3 4y |} ew Haven, . ‘“ aor. te 
« «5 | Providence, R. 1 ee | Ee. 
ss. & 6“ || Boston, Mass. - 10 
- From these data we find the progress of the wave to be in the 
direction N. 62° 19’ E., and velocity 30.05 statute miles per hour. 
But the course of the tornado was N. 33° 30’ E., inclined 28° 49 
to the progress of the wave. The velocity of the wave in the 
directionof the tornado’s progress was then 34.3 miles per hour, 
a result almost identical with the second estimate. The first es- 
timate can only be regarded as a good guess. The tornado then 
travelled a space equal to its breadth, at Mayfield, in seventy-five 
Seconds. — Fan 3 | ‘ Bao 4 
‘The velocity of the wind’s motion however at points of the most 
destructive violence, was far greater than this. A tolerable idea 
of its velocity may be gained from the distance to which light 
objects were driven into the ground. Small pieces of clap-boards 
with square ends were driven into turf land eighteen inches, and 
with sharp ends two feet. What charge of powder is capable of 
producing the same effect ?. According to the experiments of Dr. 
Hutton, (Tracts, Vol. 3; p. 214,) a pound ball of cast iron fired 
