432 NOR THERN CHI L E . June, 1835.
appears a consequence (and not the determining cause) of
the earthquake. I allude to those cases, when rain falls at
a period of the year, at which it is a greater prodigy than
the earthquake itself: I may instance the rain after the
shock of NoYcmher, 1822, at Valparaiso. A person must
be somewhat habituated to these climates, to understand
the excessive improbability of rain falling at such seasons,
except as a consequence of some law quite unconnected with
the ordinary course of the weather. In the case of great
volcanic eruptions, as that of Coseguina, where torrents of
rain fell at a time of year most unusual for it, and “ almost
unprecedented in Central America,” * it is not difficult to
understand that the volumes of vapour and clouds of ashes,
might have disturbed the atmospheric equilibrium. lium-
boldtf extends this view to the case of earthquakes; hut
for my part, I cannot conceive it possible, that the small
quantity of aeriform fluid which at such times escapes from
the fissured ground, can produce such remarkable effects.
Humboldt! has stated that, “ on the days when the earth
is shaken by violent shocks, the regularity of the horary
variations of the barometer is not disturbed under the tropics.
I have verified this observation at Cumana, at Lima, and at
Riobamha ; and it is so much the more worthy of fixing the
attention of natural philosophers, as at St. Domingo, at the
town of Cape François, it is asserted, thata water barometer§
was observed to sink two inches and a half immediately
* C a ld c le u g h . P h ilo s o p h . T r a n s a c t. 1835.
t P e r so n a l N a r r a tiv e , vo l. ii., p . 2 19. ! Ib id ., p . 2 1 7 .
¡5 C o u rre jo lle s , in th e J o u rn a l d e P h y s ., tome liv ., p . 106. T h is d ep
re s s io n an sw e rs o n ly to two lin e s o f m e rc u ry . T h e b a rom e te r rem a in e d
m o tio n le s s a t P ig n e ro l, in A p r il, 1808. - ( I b i d . , t . Ix v ii., p . 2 9 2 .) [ I m ay
a d d t h a t th e e a r th q u a k e a llu d e d to b y C o u r r e jo lle s a t p . 106, was
a c com p a n ie d b y a “ trè s -v io le n t c o u p d e v e n t w h ic h e x p la in s th e fall o f
h is w a te r b a rom e te r . M o re la te ly , M r. W illiam s , in h is N a r r a tiv e o f
M is s io n a ry E n te rp r is e (p . 4 4 2 ), h a s g iv en a n a c c o u n t o f a h u r ric a n e
w h ich d e v a s ta te d th e A u s tr a l islan d s (S . W . o f th e S o c iety A r c h ip e la g o ),
a n d w h ich a t th e N a v ig a to r Is la n d s was a c com p a n ie d b y a n e a r th q u a k e .
— C. D. ]
June, 1835. m e t e o r o l o g i c a l p h e n o m e n a . 4.3.1
before the earthquake of 1 7 7 0 - In ^le same manner it is
related, that, at the destruction of Oran, a druggist fled witli
his family, because observing accidentally a few minutes
before the earthquake, the height of the mercury in his barometer,
he perceived that the column sunk in an extraordinary
manner. I know not whether we can give credit to this
assertion.” Mr. Alison, in a letter dated Valparaiso, informs
me, that just before the earthquake of November, 1822, the
mercury in the tube of the barometer standing in his store,
sank beneath the graduated part. Tlie tube was a bent
on e ; nineteen inches being exposed, and the lowest graduated
part corresponded to twenty-six English inches. With
this third case, and more especially considering the unquestionable
fact of rain so frequently following severe
earthquakes, even at the most unusual seasons, I cannot conclude
otherwise, than that there exists some connexion between
the subterranean and atmospheric disturbances, of
which we are at present quite ignorant.
Mr. Miers,! in his account of the Valparaiso earthquake,
November 19th, 1822, has added one more to the list of
coincidences between luminous meteors and earthquakes.
He says “ one of very considerable size, in apparent dimensions
little less than the moon, was observed in the southward,
at no very great elevation. It traversed a consideralile
arch of the heavens, leaving behind it a long train of ligh t;
and when it disappeared, it seemed to do so from explosion—
as it leaped in the same manner as those whicli eject
meteoric stones ; but in this instance no noise was heard to
attend its extinction, nor was it known that any stones
fell. This occurred about half-pa,st two o’clock in the
morning after the eartliquake.” The earthquake itself
happened at half-past tea o’clock. Mr. Miers then adds,
that a friend of his “ travelling on the night of the 4tli of
November, about a fortnight preceding the great eartliquake,
observed at a little past eleven o’clock in the noHhern sky,
J l i e r s s T ra v e ls , vol. ¡., p . 3 95,
.
I I,
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