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number of photographs were furnished that institution, showing the uses of photography in representing lunar, solar, and stellar phenom. ena, aud in recording changes in the earth's magnetic forces and including views of instruments used for such purposes. Copies of these, I am informed, were exhibited at Cincinnati, and on their return to Washington will form part of an interesting exposition of the history of pho. tography prepared for the Museum by Mr. Smillie. Very respectfully, your obedient servant,

A. G. WINTERHALTER,

Lieutenant, U. S. Navy. The SUPERINTENDENT, U. S. NAVAL OBSERVATORY,

Washington.

U. S. NAVAL OBSERVATORY,

Washington, October 29, 1888. SIR: I have the honor to submit the following statement concerning the exhibit of the Naval Observatory at the Centennial Exposition of the Ohio Valley and Central States, held at Cincinnati, Ohio.

I reached Cincinnati June 29, several days before the opening of the exposition, and remained there until detached, October 23.

The space allotted to the exhibit of the Navy Department was the southern part of the east wing of the Park Building and the northeastern part of the south wing of tbe Government annex. Of this the Observatory exhibit was assigned a platform about 6 inches high and some 36 feet long by 12 wide along the northern wall of the annex building, which seemed admirably adapted for the purpose.

The building was not completed until July 2, at which time we began unpacking and placing the exhibit. The time-service exhibit was the first to be placed in position and was in operation at the time of the opening of the exposition, July 4. Every facility for the receipt of sig. nals and all the assistance in their power was cheerfully given us by the officials of the Western Union Telegraph Company; to Manager Page, of the Cincinnati office, we were specially indebted for raluable aia. A special wire was run from the local office to the Observatory exhibit for the use of the time-service, and was so carefully attended to that no fault occurred in that circuit during the exposition. This line and one of the Observatory time-gongs were used in opening the exposition), signals from Mrs. James K. Polk, at Nashville, Tenn., being struck on the time-gong temporarily placed on the Music Hall stage for that purpose.

The disposition of the exhibit was generally as follows: The sidereal clock, chronograph, Gardner clocks, telegraphic instruments, maps, photographs, drawings, and magnetic instruments were placed on the plat. forin in the naval exbibit. The time-gongs were placed, one near the fountain in the center of Park Building, the other over the canal in machinery ball; a third gong, a part of the exhibit of the Ohio State University, was connected with the same circuit and struck by the time signals. The time-ball was placed on a platform 16 feet high and 8 feet square, erected on the tower over the main entrance to the Park Building, on Elm street. The observatory houses, the photoheliograph and heliostat, equatorial, and transit houses, with their instruments set up for use, were placed in the southeast corner of the park, just outside the Gorernment annex.

Five clocks of the Gardner system, showing intercolonial, eastern, central, mountain, and Pacific coast time, respectively, were kept run

ping continually and were corrected daily by the noon signal. The clocks and time-ball gave no trouble whatever, responding promptly and accurately to every signal. The time signals were received with the greatest regularity; we failed to receive them on only about half a dozen occasions during the one hundred days, and only once failed by reason of a fault outside the local line in Washington City.

The observatory houses in the park were open to the public for two hours, from 1 to 3, each afternoon, and the photoheliograph image of the sun was shown every day on which the sun was visible. The equatorial house was open on clear nights, and an opportunity to view the heavens through the telescope was afforded many visitors.

I believe the Observatory exhibit was an attractive feature of the Government display, the time-service especially attracting much atten. tion. Very respectfully, your obedient servant,

A. B. CLEMENTS,

Ensign, U. S. Navy. Capt. R. L. PHYTHIAN, U. S. Navy,

Superintendent, U. Š. Naval Observatory, Washington, D. O.

REPORT OF SUPERINTENDENT OF NAUTICAL ALMANAC.

NAUTICAL ALMANAC OFFICE,
BUREAU OF NAVIGATION, NAVY DEPARTMENT,

Washington, October, 1888. SIR: In compliance with the order of the Bureau I have the honor to submit the following report of the work of this office during the past year.

PRINTING.

The American Nautical Almanac for the year 1891 was issued from the press in April, 1888.

The American Ephemeris for the same year appeared in September, 1888.

The Atlantic and Pacific Coaster's Nautical Almanacs for the year 1889 were also issued in September.

Of the Almanac and Ephemeris for 1892, 325 pages are in type.

DISTRIBUTION.

During the fiscal year ending June 30, 1888, the sale and distribution of the preceding publications were as foliows:

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The proceeds of sales, amounting to $1,401.25, bave, in compliance with law, been deposited in the Treasury to the credit of the appropriation for public priuting and binding.

There is an increase in the sales of all these publications over those of last year,

COMPUTATIONS.

The annual routine of computations has been carried on as usual. The volume for 1892 is complete, except some portions which it is not necessary to prepare long in advance of printing. All the computations for 1893 are in their usual state of forwardness. The lunar and solar ephemerides for 1894 are in course of preparation for use in subsequent computations during the next year.

NEW TABLES OF THE PLANETS. A full statement of the objects and progress of this work was made tn iny Jast annual report. The temporary disability of the superiniendent and the occurrence of two vacancies in the office force have interfered with its progress during the past year.

The whole work is divided into four sections, namely:
First. The computation of the general perturbation of the planets.

Second. The re-reduction of the older observations and the discus. sion of the later ones, with a view of reducing them all to a uniform sys. tem.

Third. The computation of tabular places of the planets from Lever. rier's tables up to the year 1864.

Fourth. The final discussion of all the results.

The first part of the work is completed for all the planets but Uranus and Neptune, with the exception of investigations to test its accuracy.

Reduction of observations. -A careful examination of Bessel's Kön. igsberg observations, 1814-1845, and of Pond's Greenwich observations, 1812-1830, sbowed that it was advisable to re-reduce both series for use in the planetary work. The former series bas just been completed, and the latter is in progress.

Some progress has also been inade in the reduction of Piazzi's observations at Palermo.

Computation of tabular places. The computation of the apparent right ascension and declination of the sun at Greenwich apparent noon, for the dates of observation at the principal observatories, is computed up to 1864, and reduced to the instant of observation for the observations at Paris and Konigsberg.

The comparison of Maskelyne's Greenwich observations of the sun's right ascension, 1765–1810, with the computed places has been completed and work upon the formation of the equations of condition commenced.

The comparison of the Paris observations of the sun's right ascension with the results given by computation is completed for the whole series up to 1882; it being only necessary, in the latter part of this series, to reduce the comparisons published by the Paris observatory to the adopted standard of right ascension.

The computation of the geocentric places of Mercury for the dates of the Palermo observations, 1791–1813, has been completed in the first part; the second or duplicate part is still unfinished.

The computation of the geocentric places of Venus for Greenwich mean noon, and the daily variation of the same, has been completed up to 1864, with the exception of a few dates previous to 1830.

The geocentric places have also been interpolated to the instant of observation for all the observations at Greenwich previous to 1830; but this work of interpolation still requires some checking to insure the necessary degree of accuracy.

The computation of the geocentric places of Mars has been completed as far as 1850, and the concluding portion, 1850–1864, is about half fin. ished.

Theory of Jupiter and Saturn.-Since my last annual report the pro. visional tables of these planets have been completed by Mr. Hill, who is now engaged in a description of their construction and use. These tables are still to be corrected by comparison with observations since 1750. The work of correction can not, however, be finally completed until that on the four inner planets is ready.

Mass of Jupiter.—Yet another branch of the planetary work is the de. termination of the mass of Jupiter from the motions of Polyhymnia. As stated in previous reports, the perturbations of this planet hare been computed from the epoch of its discovery in 185t up to October, 1888. The work awaits observations during the opposition of September and October, after which the final discussion can be taken in hand. These observations have been particularly requested from seven observ. atories in this country and Europe. Very respectfully, your obedient servant,

SIMON NEWCOMB,

Superintendent Nautical Almanac. The CHIEF OF THE BUREAU OF NAVIGATION,

Navy Department.

No. 7.-BUREAU OF ORDNANCE.

BUREAU OF ORDNANCE, NAVY DEPARTMENT,

Washington City, October 31, 1888. SIR: I have the honor to submit the annual report of this Bureau, and also to transmit estimates for the fiscal year ending June 30, 1890. (1) Fuel, tools, material, and labor; prizes for enlisted men; proof of naval

armaments; batteries of the new types for two ships now in service;
towards the general armament of the Navy with modern secondary
batteries and small-arms ..

$514, 150 (2) General repairs to ordnance buildings, magazines, and appendages.... 15, 000 (3) Freight and miscellaneous expenses....

10,000 (4) Civil establishment at navy-yards ........

24,980 (5) General expenses of the torpedo station, torpedo-boat marine railway, and enlarging torpedo-boat house......

70,000 (6) Towards the armament of vessels authorized ........

4,077,000 (7) For completion of the gun plant at the Washington navy-yard ........ 625,000

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The number of high-power steel cannon for the Navy completed to date is as follows: 5-inch ....... 6-inch .. 8-inch ...... 10-inch ...

Since the last annual report was made a new design of 6-inch gun has been completed and thirty-two of these guns are in process of construction at the navy-yard, Washington; at the West Point Foundry, Cold Spring, N. Y ; and at the South Boston Iron Works, Boston, Mass. The navy-yard, Washington, has practically finished ten.

This design is in several important respects superior to those here. tofore in use. The tube is hooped to the muzzle, thereby greatly strengthening it against strains in the chase. The powder chamber has been reduced in diameter, thereby enabling us to reduce the exterior diameters of the body of the gun, and to save sufficient weight at that point to enable us to hoop the gun at the muzzle without any increase over the weight of the former models. The rifling of this gun is somewhat different from that of those that have heretofore been built, and it will be seen in cross-section in the appendix. The groove removes less metal from the gun than is the case with the ordinary groove, and will probably be subject to less erosion from powder gas. The twist increases from zero at the origin to one turn in twenty-five calibers at the muzzle, the curve being the semi-cubical parabola. The

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