The Hawaiian star. [volume] (Honolulu [Oahu]) 1893-1912, 1902-06-09
THE DARK ROOM
NEAR SISAL
CONTINUED from Page u

pole. Here in Hawaii the compass
points degrees and Z minutes east of
the pole.
These figures are subject to in
cessant variation. There is a daily
variation and cyclical variation. AS
natural consequence of such varia-
tons, compass surveys of land are
very often inaccurate. 4 survey made
a hundred years ago, though perfectly
accurate then by the compass. if made
ever again today, might develop quite
different boundaries of a given piece of
land
The small building at Sisal contains
not single piece of iron or steel, aside
from the needles. Every nail USED in
the construction of the building is cop
per, The inner chamber is kept at a
steady temperature with the greatest
care, and it is SO protected that it is
absolutely steady and protected from
light. 1t is approached through a small
porchWay, in which the visitor opens
and closes three doors before he is in
the chamber where the Instruments
keep up their steady work. Here, with
three feet of sawdust and air between
the inside wall and the outside on
which the sun is beating, the condi-
tiOns as to light and heat vary very
little.
The photOgraphing of the movements
is done by a camera worked by clock
work. a mere speck of light which
cannot be detected by the unframed
eye, sends the motions of the needle to
the mirror of the camera, and the
speck describes a line across the SEN
sitive sheet. The movements are cal
culated by the deviations from a
straight base line, and the variations
in intensity of the force in the same
way.
There is a general uniformity in the
phenomena exhibited by the needle.
The maximum deviations are observ-
able at about the same hours each day,
and the observer states, appear to have
some connection with the height of the
sun. On certain days, however, there
are magnetic storms" These are sud
den violent disturbances in the cur
rents, felt most severely in the far
north Scientists are utterly without
explanation of them and theories run
wild, the sun spot theory being the
most widely known to the public.
The greatest such storm observed
here was on the day of the outbreak of
the volcano at st. Pierre. on that day,
for about six hours there was very
marked reduction of intensity in the
magnetic force. The same conditions
less marked, We're observed on several
subsequent days.
1t is expected that the work of the
many stations will be of great benefit
to naVigatOrs as well as to surveyors.
| The variations of the compass are so
great and SO Changeable that they may
lead, and have led, to most serious err
rors. There are places on earth where
the needle points east or west, and in
one place between the magnetic north
pole and the geographical north pole, the
north end of the needle points due
south. The present great series of ex-
periments may result in discoveries
| that will explain these differences and
il, the compiling of tables and maps Of
| information that will greatly assist
surveyors and navigators,
| Some distance from the observatory
! the observers have a small home. The
| location was chosen for it's isolation,
! for there must be no disturbances. The
| approach of electric cars, or the pres
| ence of any quantity Of steel or iron,
| for instance would prevent the needle
| from impartially recording the earth 5
currents, by introducing a local ele-
| ment.
For these reasons the observatory
| was placed in the midst of a great
coral plain, In which lantana and a few
| algeroba trees are the only growth
! There is work enough, ia connection
with the preparation of the reports, to
| keep the observers busy most of the
! day. The station need not be visited
more than a couple of times a day, for
| the instruments steadily make their
| own records, and the fewer visits are
made the better, for every time a door
! iS opened and a human being goes in,
! there is some change in the tempera-
! ture. Fleming and Weinrich wear no
| clothes that contain iron or steel
| even in the buttons and wear slippers
| that contain no nails.
A siesmograph is TO be added to the
! Instruments at the station, a place for
! i, having been made in the room where
| the other Instruments are