The Vancouver independent. (Vancouver, W.T. [Wash.]) 1875-1910, 1882-06-15
SOME NATURAL WONDERS.
BY PROF. THOMAS CONDOR.

| the above head communication from
Adam Duncan of Priest Rapids, in re-
gard to some natural wonders of that
region. One of these is lake, which,
} though near the rapids of the river,
rises when the river is lowest, and
falls when the river is at its height,
until nothing is left of it but dry
bed, perforated by number of large
wells of widely different kinds of wa
ter. Another of these wonders is de-
scribed as a natural ice factory, in
which the ice is formed in mid-sum-
mer.
An extensive and very interesting
group of facts of my own observation
is at once recalled by Mr.. Duncan's
pathetic inquiry "Why is all this
thus?" While the explanation I am
about to attempt is only intended to
apply directly to the ice formation in
summer, l have strong conviction
that it will give a clue to an equally
clear explanation of the other, be-
cause the two facts are really closely
allied.
Several years ago an ice cave was
discovered in Washington Territory,
a few miles west of one of the branches
of the White Salmon river. The sup
ply of ice in this case was so good and
abundant that pack trains were loaded
with it for the Dalles market, and
once or twice profitable shipments of
IL reached Portland. That this ice in
White Salmon river was formed in
spring and summer was plain, for, as
Mr.. Duncan observed of the ice in his
cave, it accumulated in icicles or stall
actite masses and in warm weather,
while the water that thus froze plainly
came from the external surface, trick
| ling through the roof of the cave. On
examining the interior of the cave, a
dark opening was found through
which strong current of cold air
| flowed into the cave. The trickliEg
water from the surface to the roof, the
stalactite form of the ice, and this cold
current of air, suggested to me at the
time / examined them an explana-
tion. But, instead of narrowing the
problem, the explanation widened it,
so that it claimed other groups of facts
in the same region, kindred to its
own. A short disgression will enable
us to- gather these into our theme.
Our party found other caves in the
neighborhood without ice; most of
those examined we found ahounding
in evidence that currents of melted
rock once flowed through them. Por-
tions of this still hung to the roof in
ropy masses or more slender drops;
other twisted fragments adhered to
the sides of tide passage. We broke
off specimens from roof and ledge, so
plain and demonstrative that no one
of us doubted that we were standing
on the bed of an ancient lava flow;
one that flowing for months had
abundant time to cool and harden in
its motionless portions, and on its sur
face into thick sheet of basalt rock,
while a narrow stream of fresh hot
lava kept up a running current down
through this duct.
| If now we suppose the supply sud-
denly arrested by some change in the
crater, plainly this narrow stream
would run out, leaving long, empty,
cavernous passage in the rock. But
now the relationship of these facts:
First, our ice cave was one OF these
old lava ducts, differing from the
others only in its ice supply. Second,
why this difference? These lava ducts
were once very numerous, most of
| them having been broken up by
subsequent violence; a few still remain
entire; these entire ones are now un-
derground passages from the crater on
the mountain, or some opening con-
nected with it to the place OF discharge
in the valley or plain below. While
winter lasts there Is no downward
current in this passage, for the air 10
, cold at both ends; but April, May and
June change all this, making 1t warm
in the plain below, while 1t Is cold on
the mountain top only; this difference
increases after sunset, and the weight
Of this cold air of the summit presses
through the old lava duct, forcing the
summer air out of the cave, and SUBJ
stituting this freezing air Of the noun
tain top, thus continually adding at
night to the mass of ice not melted on
the preceding day. have no doubt
Mr.. Duncan's lice formed In midsum-
mer'' can be explained in similar
way.
These underground lava ducts, ac-
cessibie and inaccessible, are far more
numerous than one would suppose,
often causing the hollow ground per-
ceived in riding over surfaces OF ba-
saltic rock that they often commune
cate with lakes on the surface, caus-
ing them to rise and fall by reason OF
varying supply Of water, might be
expected. Gravely lake, near Tacoma
is an instance In point 1t is without
visible inlet, yet rises Ia midsummer
to such : height aboveits winterstage
- - L.