The Hawaiian star. [volume] (Honolulu [Oahu]) 1893-1912, 1905-09-20
COMPASS VARIATIONS
TO Be HER QUEST
Continued from mage one.

cruise for scientific purposes. At pre-
sent the brig is awaiting the accurate
adjustment of her instruments at the
Sisal observatory and she will probably
sail on her wandering quest in about
three days.
Our principal work is to determine
the variation of the compass at sea-"
said Captain Pratt. Here he drew
attention to an deliberately decorated
chart which was pegged to the side of
the Galilee's cabin. 1t was a map of
the world on Mercator's projection but
it was crossed from top to bottom with
hundreds of red lines which described
curious curves and from left to right
there were blue lines which wavered as
they swept across the sheet.
"The red lines which run from north
to south mark the places, as nearly as
so far determined, where the variation
of the compass is e same" said Cap
tain Pratt. You will notice that there
are two broad lines running clear
across one by the eastern part of South
America and thence through the United
States and Canada and terminating up
north of Hudson Bay. The other is
in the eastern hemisphere. Those lines
mark the places where there is no de-
Walton in the compass, that is to say
along those lines the needle points di-
rectly to the true north East of the
western line the compass will point
west of north and here on the Pacific,
for instance, it points east of north
THE blue lines which run across the
chart represent the variation i'm the
dip of the needle, that is to say the
degree i'm which compass is inclined
from the horizontal position in different
places.
"Of course this may seem small
matter to the layman but it is very
important to the seaman and of alb
sorbing interest to the scientist" con-
tinued Captain Pratt. What causes
the variation? Well, if l. or anyone
else could exactly answer that ques-
ton perhaps these researches would
be unnecessary. It's a fact that there
is a variation and it is also a fact that
the variation is changing. The mag
netic pole is not fixed quantity and
hence polarity alters all the time.
1.-THE present charts are based on
data which runs back for over hum
dred years, data collected from all
sources, but the present trip of the
Galilee is, 1 think, the first ever under
taken for the express purpose of de-
termining compass variation. Even
on the way down here, though we had
not really begun experiments, we found
that there was an error on the chart,
at about 145 West % North the chart
is wrong nearly a degree, of course it
has happened that there has been no
observation taken at that point and
the men who prepared the chart had
necessarily to go by what there was
in the way of records i'm the nearest
points.
II think that our mission will be of
I the utmost value to the shipping as
well as to the scientific world" con-
| cluded the captain.
The Galilee while here is undergoing
a most careful overhauling Wherever
/ possible metal is being replaced by
! nOn-metallic substances so that the
delicate instruments may not be affect
ed i'm any way whatever. Steel
cables have given way to hemp and IT
! would not be surprising If the captain
! has discarded silver spoons in favor OF
wooden ones. Captain Pratt himself
| Is one of the best qualified men in the
world for the delicate work he has in
charge. His last few years have been
spent i'm the north and he was for a
long time employed with the joint
Canadian and American commission
which fixed the much-veXed question
of the boundary between Alaska and
British Columbia.