Delaware journal. [volume] (Wilmington [Del.]) 1827-1832, 1828-07-04
Abstract Of paper on the Phenomena Of Volcanoes
by Sir Humphry Davy, Bart. F. X. S. read at the


meeting of the Royal Society, March Goth, 1918.
In an article the decomposition of the earths,
published in the Philosophical Transactions for
1872 the author offered it a conjecture, that the
metals of the akalies and earth might exist in the
interior of the gobe and on being exposed to the
action of air and water, give rise to volcanic fires,
and to the production of layas, by the slow cooling
Of which, basaltc, and other crystalline rocks,
might subsequently be formed. Vesuvius from To-
cal circumstances, presents particular advantages
for investigating the truth of this hypothesis; and
of these the author avaed himself, during his resi-
dence at Naples, in the month of December, 1919,
and Of January and February 1920. small err
upton had taken place few days before he visited
the mountain, and stream OF lava then fow-
ing with considerable activity from aperture in
| the mountain little below the crater, which
throwing up showers of red hot stones every two or
three minutes On its issuing from the mountain
it perfectly fluid and nearly white hot: its
face appeared to be in violent agitation, from the
bursting Of numerous bubbles, which emitted clouds
of white smoke. There was no appearance of more
vivid ignition In the lava when it was exposed to the
air, nor did it glow with more intensity when it
raised and poured out by an iron ladle. A portion
was thrown into blass bottle, which was then clos
ed with ground stopper; and Oh examining the
air in the bottle, time afterwards it found
not to have lost any of its oxygen.
i Nitro, thrown upon the surface Of the lava, did
not produce such an increase of ignition as would
have attended the presence OF combustlbe matter
The gas dlsengaged from the lava proved, on ex-
animation, to be common air. When the white
vapours was condensed OH cold tin plate, the de-
posit was found to consist OF very pure salt;
aud the vapours themselves contained nine per cent.
of oxygen, the rest being azote without any notable
proportion OF carbonc acid sui phereous acid gas
SEES although the fumes Of this latter gass were ex
ceedingy pungent in smoke from the Oater of the
volcano. On another occasion. the author examin-
! ed the saline incrustatlons the rock the
: cien bocca of Vesuyus and found them to consist
: Principally of common salt, with chloride us
lron little lphate Of soda. still smaller quant-
ty of suphate of muristc Of potassa, and minute
portion of exde of copper In one instance, in
which the ckrysals had purplish tint, trace of
lnuriate of cobalt detected. From the obser-
~ vations made by the author, at different periods he
= concludes that the dense white smoke which in
81 immense columns from the stream of lava, and
~ which reflected the morning and evening light of the
purest tnts OF red and orange, produced by the
- salts whce submated with the stream; it pre-
sened striking contrast to the black smoke arising
from the crater, which loaded with earty parti-
:, ces, and formed black clouds, which in the night
If we're very luminous at the moment of the expo:
= sion.
II The phenomena observed by the author afford a
al sufficient refutaon of all the ancient hypothesis, in
~ which volcanic fires were ascrlbed to such chemical
- causes the combustion of mineral coal, the actor
~ of sulphur upon iron and they perfectly CON
no sstent with the supposon of their depending upGr
al the oxidation of the metals of the earths ex
=, tensve scale, in immense subterranean cavities L
which water or atmospheric air may occasionall,
have access. The subterraneous thunder, heard a
I'M great distances under Vesuvius prior an eruption
ne indicates the vast extent of these cavities and the
ne existence of subterraneous communication betwee
tx the Solfaaro and Vesuvus is established by tn
ers fact that whenever the latter is in active state
'ys the former is comparatively tranquil In confirms
ON ton Of these views the author remarks, that aimo
me all the volcanoes of considerable magnitude in tn
ora old world are in the vicinity of the sea and
1E those where the sea is distant, as in the
canoes of South America, the writer way be supple
from subterraneous lakes for Humboldt, stat,
some of them throw up quantities Of fish. The al
ben thor Acknowledges however, that the hypothesis of Il
nucleus of the globe being composed of matter
the Quilted by heat offers at more simple solution
itch the phenomena Of the volcanic fires.
on
-nal From the National LntelHgeacer.
de- TENNESSEE.
the Letters from this State assure us that the Pre-
WIS., dental election will be very warmly contested thci