The evening times., 1898-12-08
OPERATIONS OF THE
NAVAL OBSERVATORY
ANNUAL REPORT OF THE CHIEF
Search for d'Arrest's Periodic Com
et-Articles Added to Perma-
nent Equipment.

reau of equipment Navy Department,
contains much that is of interest.
The 26-inch equatorial telescope was en-
ployed almost exclusively on faint and
difficult objects. which could not well be
| reached by smaller telescopes. The work
accomplished during the year was as fol-
| lows:
D'Arrest's periodic comet was sought
for on almost every favorable occasion
from July to September g. 1897, but it
was generally difficult TO see on account
of its position in the southwestern sky,
which is Illuminated by the electric lights
Of the city, and only nine observations
were obtained.
Giacobini's comet was observed on June
2l. 1898, but as it was visible in the 5-inch
| finder its further observation was left to
| the 12-inch equatorial telescope.
The observations of the relative posi-
| tions of Titan and Tapetus during the
years of 1894, 1888 and 1896 gave for the
mass OF Saturn l. and as that falls about
| half way between the value found by
Prof. Asaph Hall and the group of values
found, respectively, by Bessel, II. Struve.
|
! difficulty of avoiding systematic errors in
observing satellites. AS the latter group
OF values is supported by the result OBJ
| tanned by DR.. George w. Hill from the
| perturbations OF Jupiter and Saturn ii
| has been surmised that the observations
| of the relative positions of Titan ar,r Ia
! petus may have been yitiated by the su-
| perIor brightness of the former. and
therefore it was decided TO attempt
g aTETT iln.4f5 Of
| observations of the relative positions OF
khea and lapetus- That work was be
gun on May 16 1898.
| Observations Of the satellite of Neptune
were attempted on almost every possible
occasion from October l3 1897 to March
| IL. 1895 and forty-one complete measure
| ments OF position angle and distance were
| obtained.
In order TO determine correct formuiae
| Tor the semidiameters of Mercury and
| Venus il is desirable to have measure
| ments of these planets in all parts of
their orbits, and To that end watch
has been kept upon them, and measure
| ments have been made with the flar mi
| crometer whenever the seeing was suffi-
| cientiy good. During the year the di-
| ameter Of Venus has been satisfactorily
! determined on sixteen occasions and
| that of Mercury on three occasions. the
| Aia'iA4 1SiltS il Instance unity Delng Tor
| the diameter Of Venus 17.47 seconds and
| Tor the diameter Of Mercury T2I seconds
| Observations Of difficult double stars
| nave been continued on the same general
| plans as in previous years. and, as usual
| the work has been much impeded by the
| paucity OF nights on which high-na gni-
| tying power could be satisfactorily used
| At the request OF Prof. S ". Burnham.
| large number OF close doubles discov-
I ~ i'm ftarl rl.tl.a u {y
| serving list, and observations were be-
! gun on them in October 1897 Most Of
! these stars require a power of at least
| 800 to divide them satisfactorily. but out
| of tifty-four nights, during which 130
| pairs We're observed. there We're only ten
| nights on which a power of SSS could be
used, and on only three of these ten did
| the favorable conditions last SO long as
| two or three hours
Throughout the year much Of Prof
| Browns time has been absorbed by the
| work of inspecting and surveying instru-
| mentS belonging TO the nautical branch
| of the Observatory. and, on account of
| the detachment OF officers for the war
| with Spain, since May he has acted as
/ storekeeper. and his days have been al
most entirely occupied by the inspection
| and issue of nautical instruments to the
| navy. He has also made an investiEa-
ton and report upon the p~a-- ondi-
| ton OF our magnetic observatory. in
! Guiding a comparison of its methods and
| results with those similar establishments
| in other countries
The Pinch equatorial telescope was
! employed during the year in observing
comets minor planets, occulta,ions Of
! stars by the moon. eclipses of Jupite-'s
satellites, and in determining the pos
items of a few faint stars for the 26-inch
| f.ll
A. follows:
| Thirty-one observations of astero d :
were made. namely: one of Hebe, fl e
OF Iris. three Of Partheaope. two of The
| mis- six of Danae. two of Cybale. one of
! Ophelia, seven of Prokne one of Unitas
and three of Eucrate.
Perrine's comet was observed twelve
| times.
Coddingtons comet was observed three
| times.
Giacobini's comet was observed once.
| The positions of nine misc cellareous
| stars were observed for use in connection
with the work of the 26-inch teles ope.
Four occultations of stars by the mool.
and fourteen eclipses of Jupiter's satel-
| lites were observed.
| The above observations are all COM
| pletely reduced.
During the year the following named
| articles have been added to the perma-
nent equipment of the astronomical
| department: One Weston's standard
portable alternating and direct current
| voltmeter, one Westons direct reading
| ycltmeter, one Weston's direct reading
| ammeter. There was also received new
cover for the heliostat and objective Of
the 40-foot photoheliograph: one polished
mahogany box. with lock and key in
which are packed the micrometer and
eyepieces belonging to the 96-inch equa-
torial telescope, and two polished mahog-
any boxes in which are packed various
pieces of apparatus belonging to the 914-
inch transit circle
| Upon the retirement of Prof SIMON
| Newcomb L. S. N. in March. 1897 he
was appointed to supervise the compile
ton of his tables of Mars Uranus and
| Neptune, and since then he has con-
stantly had the services of two of the
best assistants in the office, and when
ever he desired additional computers
they have been furnished him so far as
| they could be spared from other dut es
The manuscript of the tables of Mars
was sent to the printer on January Is
1898, and the composition and stereotyp-
ing were completed in the end of May
but on account of the extra work en- all
ed by the war with Spain the printing is
not yet commenced
The German Policy
| (From the Kansas City Starr
The Emperor is extremely solcitous for the ex
pansion of Germany. Instead of permitting Ger