The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1856-1888, 1875-05-01
PROGRESS OF THE GOVERNMENT
SURVEY.

Those who are interested in the progress of this
enterprise will be glad to know that the series of
triangles forming the framework Of the survey Of
Oahu has been completed by Professor Alexander,
the final junction having been made last week by
q line nearly Is miles in length, joining the station
on the promontory Of Mokapu, in kaneohe, with
that on the tongue Of land at Laie, a few miles from
the extreme north point Of the island. The third
point in this final triangle lie ON the summit Of
the sharp peak at the common head Of the Wal
kane, Hakipuu and Kaaaws valleys. The whole
series Of ~triangles nun bers about thirty, with
sides varying from three to eighteen miles in
length, the whole circuit being over one hundred
miles. In determining the position of the Laie
station by progressing from the original Waikiki
base around by Makapuu. or the east point of
the island, and also by progressing around
through Eva and Waialua Cby the west), the
difference in the two results is found to be not
over ftco feet. certainly not a dangerous error for
a hundred mile stretch of survey while the
direction, or azimuth Of the joining line as like
wise determined from both ends Of the system,
was found consistent with itself down to a single
second of arc. This speaks well both for the
l2-inch theodolite, aud the manner in which it
has been used.
Hundreds of secondary triangles for district
work have been or will be measured from the
primary series. The Professor is now engaged in
carrying the primary series across the channel to
the Islands of MolokaI and Lanai, where the
connection and verifcation can be made with the
Maui system. For signals to be observed at such
distances an ingenious little instrument is used,
long known in extensive trigonometrical work.
1t is called the heLOtrOpe; by the British observers
hehoStdt; and consists simply Of a very perfect
little plane mirror, mounted on a tripod, with
sights and a~pertures so arranged that the rays of
the sun can be thrown in any desired direction
without materially losing their power by diverg-
ence. This diminutive arrangement stationed on
MOlokai, wa actually distinguished with the
naked eye on Monday of this week from Mokapu,
a distance of about forty miles. There is hardly
any doubt but that with a clear atmosphere and
good telescopes, it can be seen as far as the curry
ature of the earth will permit. Added to this,
it can he very readily used with a little practice
as a means of telegraphing any little bits of
information required by the operators.
1t should not be imagined that because the
triangulation is completed, Oahu is surveyed. 4
great deal of strictly " Land Office Work de-
wolves upon the department, and only those con-
yersant with the land system of these Islands can
have an idea of its intricacy, and the labor
attendant upon the faithful survey of any district
or portion thereof, SO soon as boundaries are to
be mapped out. A thorough chart of the coast,
with soundings, from Diamond Head to Barber's
Point, is in course Of preparation conformity by
the Government Survey and the officers of the q.
S. S. Pensacola, under the direction of Admiral
Almy. The c~oastline of the whole island will
soon be delineated with accuracy, the accomplish
meut of which national duty will form really an
era in Hawaiian civilization. AS the public are
welcome to whatever information can be given at
the Office of the survey, aud as the work is for
general benefit, it is hoped that all who have in
formation to furnish in the way of maps, any
ways reliable, or in other methods, will not adopt
the too common idea that the Government is,
like haoles, to be made to pay double prices for
everything required.