85 
On Electrical Phenomena observed at Sea. 
lively satisfaction which he experienced, when, in 1792, M. de 
Schlottheim, one of the most distinguished geognosts of the 
Frey berg School, began to make these relations the principal ob- 
ject of his investigation. Positive geognosy enriches itself with 
all the discoveries which have been made regarding the mineral 
constitution of the globe ; it contributes the most precious mate- 
rials to another science, improperly called Theory of the Earth ; 
and which embraces the first history of the catastrophes of our 
planet. It reflects more light upon this science than it receives 
from it in return ; and, without calling in question the ancient flui- 
dity or softening of all the rocky beds (a phenomenon which is 
manifested by fossil organic remains, by the crystalline aspect of 
the masses, and by the rolled pebbles or fragments imbedded in 
the transition and secondary rocks), positive geognosy does not 
pronounce on the nature of those liquids in which the deposits are 
alleged to have been formed, on those waters of granite , por~ 
phyry and gypsum , which, according to hypothetical geology, 
have successively covered the same points of the globe *. 
Art. IV. On certain Electrical Phenomena observed at Sea , 
with an account of the Fire cf St Elmo . 
Of all the dangers to which the seaman’s life is incident, 
there is none so fearfully sublime, when viewed at a certain dis- 
tance, or so dreadfully appalling, when under the impulse of 
immediate contact, as that combination of meteorological and 
electrical phenomena, known under the common name of “ thun- 
der and lightning.” In the dark midnight of an autumnal 
cruise, as repeated through a series of years upon the southern 
shores of France, by the unremitting perseverance of the British 
Fleet, these various sensations have been experienced by thou- 
sands. In the midst of a numerous fleet of “ Britain’s best bul- 
warks,” exposed on such a night to sudden squalls and baffling 
shifts of wind, when the uncertain drops of rain fall few, but 
heavy on the deck, — -when the ship, at times unmanageable, 
rolls in the trough of the agitated sea, — when the distant thun- 
* Translated from Humboldt’s “ Essai Geognostique sur Ie Gisement des Roches 
dans les deux hemispheres.” 8vo, Paris, 1823. 
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