ON THE FACTS OF EARTHQUAKE PHZNOMENA. 71 
have any connexion, whether close or not, with earthquakes and eruptions of 
voleanoes. It has certainly been sometimes remarked that great heat has 
preceded an earthquake, but there have been fully as many examples where 
very violent earthquakes have occurred at all degrees of atmospheric tem- 
perature, and at all seasons of the year; so that heat preceding an earth- 
quake can by no means be considered asa regularly occurring phenomenon ; 
which likewise in the work of Herr Kries, already quoted, is clearly proved. 
“Tt must also be admitted, on the other hand, that changes in atmospheric 
temperatute may be a consequence of earthquakes, since there are undoubted 
instances where, after violent and widely-spread earthquakes, such changes 
in the condition of the atmosphere, and especially in its temperature, have 
manifested themselves, which may with probability be ascribed to the forces 
which produced the earthquake, at least until some other cause for them be 
observed. 
* On the whole, it is more probable that earthquakes, volcanic eruptions, 
and the whole of the fiery process carried on beneath the surface of the earth, 
may exercise some influence on the atmosphere, than that the foregoing 
phenomena occurring in the atmosphere; react upon this process; which 
belongs to the earth and manifests itself in such an energetic manner. In 
all relations between this earth and its atmosphere, the former is to be con- 
sidered as the principal (principale); and the latter only as its appendage 
(accessorium). The atmosphere is the child of the earth and is supported 
by it. Jts influences do not extend beyond the actual surface of the earth, 
but the internal operations (einwirkungen) of the latter appear solely to de- 
termine the condition of the atmosphere; with the exception of the influence 
which the sun and moon exercise upon it, which however with respect to 
terrestrial bodies, at least as far as relates to meteorological phenomena, is 
only superficial. Of tlie great cosmical influences; as attraction and such 
like; we naturally do not speak here.” 
On these observations of Von Hoff I would remark; that when we consider 
the powerful effects in heating or cooling of the air which the earth's surface is 
eapable of; as manifested to our senses, in the oppressive feel and closeness, 
&e. of an overcast or clouded summer night, when free radiation is greatly 
impeded; or conversely; of the dew produced by the free radiation of the earth’s 
heat outwards, we readily perceive what great meteorological changes, in fog, 
heat; vapour; rain, meteors, &¢., may be producible by the local overheating 
by only a fraction of a degree of a vast supravolcanic district of the earth 
before, or during; or after an earthquake; and thus violent perturbations of 
season and weather, followed by pestilences and failures of crops, cease to be 
wonderful, as doubly secondary effects of earthquakes, especially within the 
tropics; where the natural limits of every sort are so wide and so suddenly 
passed into. 
“ΤῸ follows,” says Dolomieu, “ that the atmosphere is not so immediately 
_ connected with the interior movements of the earth as has been so inces- 
i santly maifitained; and it is probable that the tempests (in the Calabrian 
earthquake) experienced in the Strait of Messina and in other parts of the 
_ Coast; may have been due to other causes.” Perhaps so, but certain it is 
_ that the earth acts far more energetically upon the atmosphere than the latter 
: ean ever react upon the earth as respects earthquakes. 
} If several, or even but a few, surprising phenomena once manifest them- 
[ἢ selves at the same time (or still more if this occur several times); or follow 
_ tlose upon each other; the world is only too much disposed to look for a 
ξ eonnexion, or even a relation of cause and effect between them; so as to make 
_ them forget the more commonly occurring events which accompany these 
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