The San Francisco call., 1896-11-24
FINDING A NEW
MERIDIAN HERE
The United States Geodetic
Survey Relocating
Itself.
The Observatory on Lafayette
Park Being Moved to
the Preside.
Professor Davidson Must Find An
other Building as the Old One
Will Be Demolished.

the Pacific Coast and from it all lines OF
longitude will be measured and all scien-
tific work of the United States Coast and
Geodetic Survey will have its base. This
much is certainty from the fact that the
Geodetic Survey Observatory in Lafayette
Park at Laguna and Wash ington streets
is being moved to the Presiuio reserva-
ton.
The change has double significance,
so it is claimed by those who know all
about the matter. So far Professor George
Davidson has entree to the station on the
Lafayette Park hill, where he has an
astronomical telescope and other instru-
ments in a house of his own within the
Government fence. Now, however, ne
may have to find another spot for his
observatory, as the geodetic people are
about to abolish the station. The propo-
sition is to raze the Government buildings
and fence and give back the site to the
City. This will be done Immediately the
new observatory at the Presidio has sui
hcient Data to define its exact position.
Ard then Professor Davidson viii be left
alone in his little observatory in Lafayette
Park at the mercy of the Supervisors.
The station at the Presidio is finished
and has just been fitted up with necessary
instruments and accommodations for the
observers who have commenced their
scientific work there. The old and new
stations are connected by telegraph wire,
which unites two transits and break Cir
cult chronometers used in the present
observations to determine the difference
in longitude between the stations. Two
officers are assigned to this work, with
transmitting signals and observing tran
sits.
Just as soon as the longitude of the new
station is determined the old one will be
abandoned, but then the precaution will
be taken to mark its exact site with stone
monument so 1t can be used as scientific
record at any other time. And should the
City hereafter lower the grade then the
monument will be lowered under the di-
rection of the proper authorities to the
new surface.
The observatory in Lafayette Park was
established in 1879. and has since been
used as the primary station for telegraphic
longitude and latitude and specific gravity
observations. From 1t ali other stations
on the Pacific Coast and in the Pacific
Ocean have been connecled. 1t had its
bearings directly from Greenwich Obsery-
atoTy although in rather circuitous man.
ner. The former observatory on Wash
ington square, established by Professor
Davidson in 1867, was connected by tele-
graph with Greenwich through the OBJ
servatory at Harvard University. When
the change was made from Washington
square to the more satisfactory one on La
fayette Park hill series of observations
were made similar to those now being con-
Quoted between the latter and the Presidio
station. In this way the Presidio Observ-
atory can claim connec ton with Green
wich.
The instruments IN the old station will
soon be moved TO the new one. They COM
prise transit instrument for obtaining
time for longitude work, a telescope for
latitude observations, large sidereal
clock and chronometers for longitude
work, with break circuit for the chro-
nometers. In addition to these Professor
Davidson has his own instruments, in
Guiding large telescope and an observa-
tory building, all of which have been at
the service of the Government free af
charge since 1880.
There exists some difference of opinion
regarding the advisability of the change.
Those VINO have had experience with the
fogs of San Francisco and other climatic
peculiarities of the City claim that it will
not be possible to do the same work at the
Presidio as on the hill. Professor David
son was asked for his opinion. He said
'They cannot make good observations
there. The station is near the end of the
Union-street Railway, in place where
fog obscures the view. During fifteen
months in 1891 and 1892, while / made
continuous observations on the hill, l
used to see the fog over the Presidio four
or hve nights at time in succession, and
hear the fog siren blowing steadily. In
such fog it would be impossible to get
and cold air down there beside the water
will disturh OhSarCariOpe