DOVE ON THE LAW OF STORMS. 217 
centres ; and we find accordingly that the force of the storm was 
particularly great there no less than at the primary centre. In 
regard to the latter, the Brest accounts say, on the 26th of De- 
cember, “ We have been living for fourteen days in the midst of 
storms, which have not ceased to rage with unparalleled fury.” 
In London there was the highest flood which had been seen 
since 1809. At Portsmouth one gust from the 8.S.E. is spoken 
of as almost unprecedented, and the sea rose to an enormous 
height. In regard to the secondary centres, the ravages of the 
storm in and around the Mediterranean were very great. From 
Leghorn to Barcelona it was terribly destructive. On the southern 
declivity of the Alps enormous masses of rain fell, and Venice, 
Genoa and Nice were overflowed. In Appenzell the tempest was 
such as the oldest inhabitants had never witnessed; it raged 
with peculiar force in the valleys; the mountains presented such 
an obstacle to the pressure of the stream of air, that the baro- 
meter stood much higher on their southern than on their north- 
ern declivity. 
We see that those barometric minima of the temperate zone, 
which are caused by the entrance of tropical whirlwinds, are 
distinguished from the same phenomena in the torrid zone by 
their greater extension as well as by the different direction of 
their course. In the case of the minimum of the 2nd of August, 
1837, the difference of barometric pressure at St. Thomas and 
Porto Rico, places scarcely twenty miles apart, was 15 lines. 
On the 24th of December, 1821, the difference of pressure at 
Brest and Bergen was only 12 lines, the amount of the absolute 
minimum being the same in both instances. On the 21st of 
May, 1823, on the Hidgelee coast, the barometer fell on board 
the Duke of York, between 8 a.m. and 11 a.M., from 325" to 
below 298", or 27 lines in three hours, as shown both by the 
barometer and sympiesometer (the fluid in both instruments ha- 
ving sunk for the space of half an hour below the visible part of 
the tubes, which began at 298"), the simultaneous fall at Cal- 
cutta having been only 8 lines. We see thus, that the fall of the 
barometer previous to the minimum, and its subsequent rising, 
take place much more rapidly within the tropics than in the 
temperate zone ; but if we consider the total diminution of pres- 
sure, we shall find that-it is much greater in temperate than in 
tropical regions. In the former it may be compared to an exten- 
sive valley with gentle declivities, in the latter to a deep ravine 
VOL. 11]. PART xX, Q 
