The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1906-09-07

/ which were also escaping in quantity
/ from the lower slopes OF the cliff.
| G . y 7 I NUAL DISCHARGE OF
+ AQUEOUS VAP0R FROM LARGE
AREAS IN THE FLOOR OF THE
GREAT BASIN OF M0KCAWE0-
/ " Eo.-This IS matter OF inport-
ance. because II would be inferred from
+ tne remarks Of some previous observ-
srs that there i at ordinary times
/ onfy a feeble discharge OF waler-vapor
/ from this vent. I have already re-
1erred 10 the fact that extensive area
| on the slopes extending northeast and
! southwest from the sxtremities OF the
great basin discharge continually a
large quantity Of aqueous vapor which
Eor the most part is only visible in
damp weather when the sun is hidden.
{ The same thing is true OF the interior
OF the great basin Of Mokuaweow 60
The amount of visible vapor varies
greatly in accordance with the meteor
illogical conditions. The effect pro-
duced by a change from a cloudless
sky with very dry atmosphere to an
overcast sky with a great increase in
the relative humidity is sometimes
startling During TIE prevailing fine
and dry weather of my sojourn on the
{
three places on the floor of the great ba-
sin When the weather was muTky and
the air charged with moisture. white
vapor became visible over the greater
portion Of the floor and a previously
smokeIess tract. as viewed from the
edge Of the basin. 500 or 500 feet above
became marked with white 'hecks" of
ascending vapor over a large part OF its
area
This phenomenon has escaped the
notice Of previous observers. so far as
I have examined their accounts. a re
suit due in most cases 10 the shortness
of their sojourn and TO the circum-
stance that they experienced only the
prevailing type Of weather. a sunny
sky and dry atmosphere. Thus. Cap
tain Dutton. whilst referring TO the
total absence of evidence Of activity
says there was mot even a wisp Of
steam and Mr.. Green basitfe his in
ference on observations made on tbs
crater and on that Of kilauea contends
that water-vapor Is but feebly evolved
from the Hawaiian vents Arguing en-
tirely on a priori grounds, Professor
Dana urges that since the air is
usually dry much of the vap0r would
become invisible. and ne thus holds 10
the old view, which he retains in op-
position To Mr.. Green, that the projec-
tile action IN the Hawaiian, as in other
vents. is due TO waUer-vaD0r C'Charac-
feristics of Volcanoes. That which
the eminent American professor 50
sarewdly sur1nised is certainly true OF
the crater of Mekuaweoweo- AS before
observed, il clear dry weather I have
walked unwittingly over extensive
lava-tracts quite ignorant of the fact
that aqueous vapor Was escaping all
around me from its numerous assures,
a fact disclosed TO me when 1 subse-
quentIy crossed the same area with the
air humid and the sky overcast
The same phenomenon came subse-
quently under my notice on the slopes
of Etna Thus in 1901 / found watery-
vapor still issuing from cracks Of the
flow of 1879, that is, after an interval OF
- years. the warmth being evident TO
the hand placed in the cracks; but the
vapor was invisible ia the bright noon
day and was only observed towards
sunset. fSee also the article Geology
in vol x D. Z48 OF the Encyclopedias
Britannica.1
SUMMARY OF THE AUTHORS
VIEWS WITH REGARD TO THE
ORIGIN OF THE GREAT BASIN OF
MOKCA WEOW EO--Basing the argu-
nsent on the examination OF the lesser
pit-craters outside the great basin,
South Mokuaweoweo IS regarded as the
Il st Of a line OF pit-craters which have
coalesced. TIE resulting cavity being
afterwards subjected 10 iateral en-
Iargemen1 and slips. s1ch as may Be
seen in progress ar tne present day
IN this fashion. IL IL held. has tie
great basin been developed This line
of pIt-craters marks the existence OF
a deep-seated assure. the source OF al
the basic Iavas that have built up this
mountain. That this great basin rep
resents the degradation OF the Noun
tain's summit can scarcely be doubted
AT The present time il not only occu-
pies the whole summit, but on the
east and west side il has been enlarg-
ing itself al the expense Of the noun
tain slopes II is. however, unlikely
that the mountain at any time was
much more than thousand feet
higher than il is now II We IN mag
ination prolong the upper slopes pre-
serving the same gradient they would
sea
The features Of greatest significance
in their iearing on the history Of the
great basin OF Mokuawecwe appear 10
ms - be those concerned with the les
ser pft-craters and with the yapor-dts-
charging areas situated at either ex-I
trenity OF the basin and displaying
rock surface much altered and some
tins re vifed- OF these two areas
tn. southern is by far the most extern
siv- As shown in the plan II was
prolonged as far as I descended or this
slope. namely TO Pohaku HanaIei,
which lies a mile or SO distant and
perhaps some 500 or 500 feet Of more
below the summit Mr.. Emerson. when
writing to me in 1898 observed that
line OF active display Of heat extends
far down the southwest slope OF the
mountain.
IT would seem that Mauna Loa has
been raised over a deep-seated assure
running y. Z. 70 s. W for distance
os AZ least ten miles, and quite inoe-
pendent OF the focus Of Kilauea- MS