"معاملات الجمعية الجغرافية في بومباي، من يناير ١٨٤٧ حتى مايو ١٨٤٩. تحرير السكرتير. المجلد VIII." [‎٢‎٥] (٤٩٦/١٢٨)

for calculating the strength of the tempest, viz., at Dodabetta, where
the force was equal to thirty pounds pressure on the square foot, when
the gale was at South-east. Now it has been ascertained that to
produce an effect equal to thirty pounds, the atmosphere, of the
density of 30-00 inches of the Barometer, must be in motion at the
rate of 80 miles per hour. It, therefore, follows, that at an elevation
of 8,640 feet, with the air reduced in specific gravity to 22*0 inches,
its velocity must have amounted to 109 miles per hour, to impress on
the pressure plate of the anemometer the force of thirty pounds.
Near the focus, the violence of the typhoon appears to have been
irresistible, and although not actually measured by a mathematical
instrument, it is possible to understand the force that caused the
foremast of the Buckinghamshire —“ a beautiful stick of eight feet in
“ circumference/ , —-to bend, a like a Malacca cane,” before the tempestu
ous blast by which it was finally blown away. The mainmast, up~
wards of eight feet in girth, was also snapt and torn out of the
vessel, and one of the quarter boats was also forced out of its se~
curings and carried across the poop like a feather.
Electrical Phenomena .—It is difficult to collect anything satisfactory
regarding the extent, nature, and duration, of the electrical phenomena
developed by the hurricane. It is quite certain, however, that electricity
was evolved at different points of the whirling masses of clouds, from the
4th to 24th, as these progressed from Ceylon to the Indus ; and, if we
may conclude from the frequent mention made of its manifestations, the
probability is that it was in constant activity during the whole time.
But whether it was more abundant or intense at one side of the
focus than another, is unknown. At Poona, an east wind, rounded
cumulous clouds, lightning and thunder, to the South and S.E„, were
the harbingers of the storm; but after the clouds settled down on
the earth, and the rain began to fall in horizontal sheets, the electrical
discharges ceased.
Loss of Pressure in the Atmosphere.—TYto diminished pressure
of the atmosphere at the centre of the hurricane, as indicated by the
mercurial column, cannot be precisely ascertained, but it may be
inferred to have been about two inches. Before the Barometers on
board of the Buckinghamshire were broken, they were observed to
stand at 28*35—about two hours before the ship got into the hurri
cane s centre. The sympiesometer, however, escaped; and when they