The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1903-12-05

recent determination bv the tele-
graphic method of the difference of
longitude of San Francisco and Ho-
nolulu through the new Pacific cable
by Messrs Edwin Smith and Fremont
Morse, of the Coast and Geodetic Sur
vey.
The first signals over this portion of
the cable were sent on January i,
1903. The cable was opened for pub
lie use on January 8, 1908. The first
observations in the Geographic deter
limitations of longitude were secured
on April 20.
: The cable company cooperated with
the government by aiding the observe
ers in various ways, and by granting
the free use of the cable during short
period each night for their work.
Between April 20 and June Is eleven
determinations of the difference of lon
gitude were made, five with the OBJ
servers in one position and six after
they had exchanged places for the
purpose of eliminating the effects of
their relative personal equation. The
total range of the eleven results was
only OF s. No result differed from
the mean by as much as one tenth of
a second.
This degree of accuracy corresponds
to that usually attained in determine
tions of the difference of longitude of
two places connected by a telegraph
line overland. Until within few
years such a degree of accuracy had
not been possible for determinations
made through long cables. The in
crease in accuracy has apparently been
due to improvements made in the re-
cording apparatus used by the cable
companies.
The difference of longitude of the
transit piers in San Francisco and Ho-
nolulu, respectively, was found to be,
from the field computation, h. 81 m.
1892 S.
A revision of\the computation still
remains to be made, but the changes
in this result will be very small. The
chances are even for and against the
difference stated, being within 0.03 s.
of the truth.
The longitude of San Francisco from
Greenwich is fixed by four transat-
lantic determine lions by the tele-
graphic method, 1866, 1870, 1872 and 1892,
and by a complicated telegraphic Ion
gitude net stretched across the Uni
ted States.
The longitude of the Transit of We
nus pier at Honolulu, as fixed by the
new determination from San Francisco
is 10 h. 81 m. 27.24 S. west of Green
witch. Taking into account all the
uncertainties in the chain of observa-
tions between Greenwich and Homo
lulu, the chances are even that the
value stated is correct within 0.06 s.,
and it is almost certain that it is not
| in error by as much as 0.62 S. In the
latitude of Honolulu 0.O6 S. of longitude
corresponds to IS feet, or ! s. to LAS
| feet.
The observers, Messrs. Smith and
| Morse, are still engaged in determining
| the differences of longitude over the
| three other spans of the cable between
| Honolulu and Manila. A good de-
termination of the difference Manila
tGuam has already been secured. Wher
their work is complete the longitude
| of Manila will have been determined
Geographically in both direction:
around the world from Greenwich, ant
the longitude girdle of the earth will
be complete.
| The following resume of various de
examinations of the longitude of Ho
nolulu is condensed from an accoun
furnished by Mr.. w. D. Alexander
, formerly Surveyor-General of the Ha
) waiian Islands. and now an assistan
in the Coast and Geodetic Survey.
is especially interesting as shown
the comparison of various determine
lions of a large difference of longi
tude by variety of methods and eS
tending over three and half Ger
turtles.
In the appended tabular statemer
the new determination of the longitud
of the Transit of Venus station, 10
81 m. 27.2 s., is taken as being corret
in deriving the errors of the varior
determinations. In cases in which tt
older determinations referred to SON
other point than the Transit of Vent
station. they have been reduced
that station by using the relations
position which are now known.
In the Spanish chart found by Lor
Arson on board the galleon which h
captured in 1743, group of islands We
laid down in the same latitude as tt
Hawaiian Islands, but II deg. too fl
east
The southernmost and largest islar
was named La Mesa, which seems
refer to Hawaii with its high tabl
land. North of it were La Desgrac
ada, probably Maui; and three sma
islands called Los Monies, which ma
have been Kahoolawe, Lanai and Nj
lokai.
This chart was published in the ma
rative of Lord Anson's voyage in ia
An official letter from the Spani:
, Photographed Department to the HI
waiian Government, dated Madri
February 81, 1865, states that an al
cient manuscript chart exists in Il
archives of that Office, in which tn