The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1868-12-30

tania, 90 feet high, ten miles from the crater.
There is still to be seen an arcade OF lava curl
ing over the same walls in places "like a
wave on the beach," Turning fortunately
aside from the city, aud advancing towards
the sea, the body of lava formed perpsnd-
cuar front, carrying before 1t huge blocks Of
granite, forming vast causeway into the sea.
In q few days, writes M. de Quatrefages,
the lava had carried forward the line of the
beach some $50 yards. The striking eruption
of 1865 is well described in letter from
French geologist, M. Fouqu6, to M. sainte-
Claire Deville. The lava stream, which in two
or three days had extended in length three
miles, with a breadth of nearly half that ex-
tent, was parted by an ancient cone, one arm
precipitatiDg iteelf in caccade of fire from a
height of so yards. The incessant hammer
ings from the ven craters were vividly sug-
gestive to the writer of the idea they gave the
ancients-that of forge in the centre OF Etna,
with the Cyclopes as workmen.
Our authors survey of the active volcanoes
carries them round the globe, and in-
cludes the latest and most distant
records of these tremendous pheno-
mena. Equally. complete and vivid is
the catalogue of remarkable earthquakes,
which are made, by the progress of scientific
observation, naturally to connect themselves
with the agency of volcanic forces. The sub
jects Of thermal springs, Of mud islands or
emissions, as well as of the singular oil or
petroleum wells lately discovered in such
wealth and extent, are discussed in their
several bearings upon each other as well as
upon the agency of subterranean fires in
general. One Of the most remarkable results
of the combined and systematic observation
brought to bear upon the phenomena of earth
quakes relates to the extent and degree over
which sonorous waves have been known to be
propagated:-
The nature of the noise also differs greatly;
fFsaau
the clanKtng of chains in the city of Quito 10
has sometimes been abrupt, like thunder close
at hand, and sometimes clear and ringing, as If
obsidian or other vitrifed masses clashed, or
were shattered In subterranean cavities. AS
SOHO BODIES are excellent conduotors OF sound,
which is propagated, for example. in burnt clay
with velocity ten or twelve times greater than
In air, the subterranean noise may be heard at
great distances from he place where 1t has orl-
ginated. In the Caracas in the grassy plains
OF Calabozo, and on the banks of the Rio-Apure,
which falls into the Orinoco, there was heard,
over district of 2300 square (German) miles, a
loud noise resembling thunder, unaccompanied
by any shaking of Inc ground; whilst at a dis
tance OF 632 miles to the northeast the crater of
the volcano OF 81 Vincent, one of the
small West Indian Islands, was pouring forth
distance, this was as If an eruption Of
Yesuvius should be heard in the north Of
France. In l74i at the great eruption of Coto
paxi, suoterranean noises, as Of cannon, were
heard at Honde near the Magdalena river. Not
lish feet higher than the Honda, bat these two
points are separated from each other by dis
tance OF 436 miles, and by the colossal noun.
tain masses of Quito, Paste, aud Popayan, as
well as by countless valleys and ravines. The
sound was clearly not propegated through the
air, but through the earth, and at great depth.
DuIinga the violent earthquake in New Ora.
NADIA, In February, 1885, subterranean thunder
and Caracas (wher it lasted seven hours with,
out any movement OF the grouud), and also in
Hayti, in Jamaica. and near the lax Of Mica
ragua.
The evidences of volcanic action in the
moon have since the time of Laplace had a
lively interest for the minds of astronomers.
There is, we need scarcely say, no longer any
idea of the aerolites which from time to time
fall upon our globe being projected from vol
canoes in our satellite, or even OF the luminous
spots or bands visible upon the lunar surface
being proofs of chronic state of volcanic ac-
tion. That changes to some extent, however,
take place in the moons substance seems
placed beyond doubt by the subsistence of a
marked crater within the last twelve months
as well as by the notifications which have
made themselves evident in the lunar maps
drawn up at definite intervals. The chapter
on this subject forms one of the best in the
volume before us. What distinguishes the
lunar volcanoes in general from our own is
their enormous size. The diameter of Cla-
vius is not less than 140 miles. Eight other
craters come between 90 and 1l3 miles, and
no less than twelve have an average of 55
miles. In other respects q strong analogy
can be traced between the aspect
of these volcanic areas and extinct
systems of the like kind in many parts of our
globe. The mountains of Bohemia, as well as
those of Auvergne, have been instanced as
presenting a confguration closely analogous
in plan to ranges OF the lunar elevations. The
luminous bands which distinguish the latter
are ascribed by Maedler to gaseous streams,
which have vitrifed portion of the surface,
and disposed themselves in rays round many
of the mountain peaks. Experiments have
been made with the result of artifcially pro-
ducing much of the process by which nature
may be conceived to have worked these sim
gular etfects:-
An English astronomer, Mr.. Hooke, obtained
an artificial imitation of the lunar cavities by
heating calcareous mud until the steam. in the
the surface In our terrestrial volcanoes, the
upper stratum of matter in fusion some-
times rises by the elasticity of the subter-
raneous gases as far as the edges of the
crater, but the dome sinks as soon as the
gases have made a passage. IL Is known that
there exist in America great extents of land
which are hollow underneath, and which are
in TACT real bubbles, II we wish to compare the
lunar surface with that of our globe, we must
In Imagination suppress the sedimentary earth
and the seas which cover the latter. Many
circles now filled up, would then appear In
Auyergne there are some very large, which are
still entirely sunken, although the granite
which forms them Is mixed up and disappears
In great number of points under thick beds
of vegetable earth. The one In the island of
Ceylon is forty three miles in diameter. In
Oceanta several madreporic islands appear To
be supported on similar circles I'VE can then
figure to ourselves" as remarked by Humboldt,
"Our satellite nearly like what our earth was IN
Its primitive state, before IL was covered with
sedimentary beds rich In shells, gravel and
diluvium, due TO the action OF the tides and
exist in the moon beds of conglomerates, and
OF detritus formed by friction"