The Hawaiian gazette., 1868-10-07
Tidal Phenomena.

The San Francisco TIfsss makes the follow
ing comments upon the tidal wave. The
only fault in its reasoning is the lack Of cor
rect data as to the time the motion was OBJ
served at these Islands
The sea was Arst observed in motion at the
wharves at 5 A n Of Aug. 14th, although it
was reported, We know not how correctly,
that some native fishermen observed the mo-
ton sometime between midnight of the 18th
and the next morning. The time therefore
must have been from thirteen TO eighteen
hours. The rise Of the sea was alike in sll
parts of the islands, about three feet and 4
half, and not ten and twelve feet on Maui and
Hawaii as at first reported. We have heard
the theory here, that the islands and not the
sea was in motion.
Another point of much interest is the
question Of the flow Of the tidal wave. We
have heard that such phenomenon occur
red at the Sandwich Islands, and We know
that it occurred upon this coast, almost sim
ultaneOusly with the earthquake in South
America But are We not jumping 10 con-
cluSiOn somewhat hastily in assuming that
the phenomena al the Sandwich Islands were
caused directly 10y the earthquake which hap
pened i've thousand miles away? Let Us ex-
annie the matter little. We will assume,
for the sake Of dsta 10 calculate from, that
the centre Of the most southern earthquake
was at Aroquipa- The difference in time be-
tween Artquipa and the Sandwich Islands is
i've hours and fifty-five minutes, and the dis
lance in geographical miles is about $500
miles. The time at which the tidal phenO-
menon was first seen at Honolulu is stated TO
have been P. NJ on the 18th OF August, and
the earthquake occurred in South America AT
P " on the same day. Allowing for the
difference OF time. this would give nine hours
and ffty-twO minutes IS the period occupied
by the tidal wave caused by the shock, in
travelling from Arequipa to Honolulu. A
scientific writer Mrs. Somerville) tells US
that the earthquake wave travels through
water st the rate Of /. go feet, or more than
two-ihirds Of 3 mile in a second. That is TO
say, the wave would, in nine hours, travel
:. SO miles, or some three thousand miles
more than the entire circumference Of the
earth This Calculation, however. is based
on the assumption that the initial rate of We
lOcity is maintained through the whole pc
riOd-an assumption which could, Of course,
never be realized. as the undulauons Of ne
cessify grow weaker in proportion to their
extent. Bearing this in mind, il NAV be
that the phenomena observed at the Sand
wich Islands resulted from the earthquake.
and this theory is strengthened at first sight
by the fact thar the use and fall Of the sea
were greatest on the eastern side Of the isl
ands-that is, on the side from which wave,
prOpagated in South America, would have
come But there are circumstances in the
accounts from Honolulu which justify US in
putting forward another theory, which, if
true, would show the extent of the subter-
ranean or submarine disturbances to have
been much greater than has hitherto been
supposed. The first and most important cir
eumsiance TO be noted, is that which puzzled
our Honolulu correspondent He says: "A
couple OF transit instruments here in town
tosre GsTOirH 0tf q letsl AID botA IN The same
direction, and not in connection either with
any perceived earthquake Now the cause
which throws a transit instrument out OF
level must be cause different from that
which merely throws a tidal wave upon the
coast; that Is to say, it must have its origin
in the place upon which the instrument is
stationed. 1t i scarcely possible to account
for this simultaneous disturbance Of the two
except upon the theory that in
stead Of the sea rising and falling around the !
Islands, the Islands themselves rose and fell /
in the sea Startling as this hypothesis may
appear, it is borne out in q very remarkable |
manner by the facts as reported. One Oh |
server writes that s'the islands seemed TO rise |
and fall and not the sea" There appears to |
have been no rare anywhere. The pheno- /
mena consisted in a receding and 4 flowing /
in again of the sea. The sea flowed out rapid |
" and returned, sometimes gradually and /
sometimes with rapidity. But there is no /
mention Of any advancing wave anywhere. 1
Just such an effect as Is described would 4
have been produced by the gentle upheaval 4
and subsistence Of the land. No such effect /
would be produced by rapid, advancing |
iidal-wave. Nor can Te. on any other theory 4
account for the deviation in the deiicately i
sensitive transit Instruments"