New-York tribune., 1899-04-12

r.r,oa e., IN. earths history. The fluid. what
ever its origin. becomes heated to tenn
perature far above the boiling point ano' III ms
Judgment possesses an explosive power Scarcely
less than that of gunpowder. When any OF
those changes in the crust Of the earth due 10
the contraction Of the globe produce hssu'e'
In the vicinity Of an accumulation OF "a'e''
the latter would tend to expand INTO s'ea"'
and carry before 1t to the nearest creVlee
GOOD deal of adjacent rock, softened II not
,,,o,,o, ana then eject the same through the
opening
Russell Gilbert and other Americans are not
ready to accept the steam" theory Ihes '''"n
,ho, Z, docs not fully explain certain observed
facts The old notion that at depth Oh wei
or thirty miles the earth is In liquid coiu'',o'
owing ~ heat is entertained by few scienunc
men to-day; but Professor Russell reearoS '"e
interior as potentially plastic Tha' Is u say
while the tremendous pressure OF the crust upon
the inner parts Of the globe Keeps tne ia''ei III
O. practically solid state. any relief OF pressure
would allow some of the underlying materiai "
,iouefy and to ooze out OF an available aperture
While admitting that steam may assist W
limited extent in producing an erupoo"' iio
fessor Russell makes relaxation OF pressure
upon potentially plastic material the mann
at WORK. HrOlessoI oo""S'
the same ground. He says
so far then. as our present knowledge goes
we seem justified in asserting that water plays
an important part in producing the explosive
nbenomena Of volcanic eruptions. and possibly
in modifying the fuidity Of magmas-the mo'eh
compound within the earth's shell; that the lavas
and scoria discharged during such eruptlohs
mo less than the igneous rocks which never
n
inal material Of the globe which have been only
slightly II at all. affected by melting down any
deposits of sedimentsry origin: that this ma
ter,al even II II has temporarily passed
into a solid condition, always has been Kept at
q temperature not far from It's melting point
that the different types Of gneous rock may pe
the result in some cases OF a Strained precipi-
tation of Advancement during the original con-
densation of the globe, but more often. In all
nrohablty of some process of differentiation
during later stages OF its history; and lastly
that the outflow Of these magmas. the intrusion
OF plutonc rocks. and the opening out OF VOL
canic oriices Of all kinds are primarily Que 10
rupture Of the crust for which no other cause
can be discovered at present than strains Set
up in consequence Of secular cooling or our
planet"
Reference has already been made to the dis
eimilarity between the composition OF the earlier
and later lavas of a given region But what mas
been indicated the rule Is often violated
Sometimes a basic lava is elected first. Some
times an intermediate variety precedes the
others What controls the order is yet problem
which the biologists are unable to solve saus-
factorily Nor can they say why the curiousiy
complex compound Of which the globe was con-
stituted while In thoroughly molten condition.
has managed to separate partially. so that one
mass is really different mixture from an ad)a-
cent one Professor Bonney thinks that the man
who would solve these and kindred problems
must be at once an accomplished chemist and
mineralogist, physicist and Mathematician
practised worker with the microscope and
field geologist OF unusually wide experience