duced. But nearly one-half the work of reduction for the zones observed with other instruments in that year had also been completed, and as it will probably be within bounds to estimate the labor required for completing the reduction of these eighteen sets of zones as being equal to that of reducing twelve volumes of the other current observations, it will be safe to say, that, while but six out of the sixteen years' current observations had been reduced, only one-ninth part of the zone reductions had been completed, although these observations were not continued after the year 1851. None of the meteorological or magnetical observations had been prepared at all.

A careful examination of the data upon which the zone reductions must be based, led to the rejection of the zones for 1850 and 1851 in total, as not possessing the requisites for successful computation. The amount of computation to be done was thus very much reduced, and the entire mass of remaining observations is now ready for the printer, with the exception of those zones which, although not containing within themselves all the clements required, can yet be provided with them by observations now making for the purpose.

It would be unjust not to mention in this connection that the Equatorial observations of Mr. Ferguson had for the most part already undergone a preliminary reduction by that gentleman himself; and that Professor Yarnall had in like manner, of his own accord, done much towards preparing his own observations with the Mural. Still, at least five-sevenths of all the astronomical work of the Observatory remained unreduced in April, 1861, as well as the whole of the meteorological observations. The magnetic instruments were not employed, as has been stated.

The volume for 1862 was ready for the printer on the 1st of January, 1863; and but for the difficulty of obtaining promptness from the Government printing-office under the present circumstances, not only this but all the observations of the omitted years would long since have been published. The observations in 1861 give the observed positions of the sun, moon, planets, and about 1680 fixed stars. Those in 1862 embrace the positions of the moon at all hours, the sun, three comets, sixteen asteroids, all the large planets, many double stars, and 2267 fixed stars. And it is believed that these observations are inferior in accuracy and correctness of reduction to none made at any Observatory existing. There is also an elaborate discussion of the longitude of the Observatory, as deduced from all the moon-culminations observed since 1845, and a series of correct illustrations of the aspects of Mars and of one of the comets as seen with the Equatorial.

Among the important duties of the institution is that of furnishing to all Government vessels the requisite charts and instruments for navigation, chronometers, sextants, compasses, spyglasses, log and sounding apparatus, &c. The balance of the appropriation for the fiscal year ending June 30, 1861, which remained unexpended when the present Superintendent took charge at the end of April, sufficed to procure the reduction of all the observations, and to equip all the vessels called into service by the emergencies of the war. During the past year the establishment has kept five hundred vessels supplied with charts and instruments, being ten times the number which the whole Navy counted before the war; and, best of all, this has been done under the now established policy (for which we may thank the zeal of the

Superintendent and the enlightened views of the Navy Department) that the productions of Ame rican artists shall always be preferred, that the best mechanical talent in the country shall be stimulated to the construction of the instruments, until we may now proudly say that better nauti cal instruments are made at home, and for a less price, than ever came to us from Europe.

The amount expended upon the Wind and Current Charts" by the Observatory under its late Superintendent was about $330,000. If they were accurately prepared, and only proper mate rial used, three times the amount would not have been too much to pay. But the Navy Department has recently referred the subject of their continuance to a committee of the National Academy; and, if rumor speaks true as to the result at which they have arrived, it may well be doubted whe ther science, navigation, or American reputation abroad have been advanced by the charts alluded to.

Such has been the history of the Naval Observatory. While on the one hand it may, perhaps, be questioned whether the advancement of science and the intellectual progress of the United States might not have been better subserved by an institution on a less restricted basis, by a truly na tional Observatory, whose officers should be appointed solely with reference to their scientific attainments without regard to naval commissions, we may find much cause for satisfaction that it is at present under the charge of an experienced observer, and that its present astronomical assistants are fitted for their positions both by taste and education. It is probably at this moment making a larger amount of good observations than any observatory in existence, the quality of the work as well as its quantity being carefully regarded, and the constant aim being to direct the energies of the institution to such objects as the present condition of astronomy most distinctly indicates to be desirable. The number of assistants is less by more than fourteen than the average number employed by the late Superintendent.

During the year 1847, a dwelling for the Superintendent was erected immediately east of the Observatory; and in the following year the cast wing was extended twenty-four feet, so as to connect it with the former building. The room thus added is used for the chronometers and other instruments belonging to the Navy. Of the four rooms on each floor of the central building, one is occupied as a library-room and office for the Superintendent; two are filled with charts properly arranged for distribution to ships of the Navy, and the remainder on the first and second floors are assigned to the assistants. clock by Kessels, and a standard barometer by Green, are mounted in the office of the Superintendent. One room of the basement has been fitted as a workshop for the machinist; instruments returned from ships and needing repairs are temporarily placed in a second one; and the other two are used for store-rooms. All of them together with the separating halls, are heated by iron pipes through which hot water circulates from a boiler under the residence of the Superintendent.

A standard

The present instruments of the Observatory are those with which it was originally provided, although most of them have since undergone some mechanical or optical modification, in every case by an American mechanician. With a short

The Meridian Transit Instrument is in the west sing. It has an object glass of 5.3 inches diameter, with a focal length of eighty-six inches and an axis forty-two inches long between the bearing points of its pivots. It was made by Ertel & Son, of Munich, and is mounted on monoliths of granite split from the same block, and which are wholly isolated from the floors and building.

"There are two clocks at present in this room. The one in use was made by Parkinson & Frodsham for the old Naval Observatory, and is supported by wood clamps to a granite pier, south and east of the Transit Instrument. It has Graham's dead-beat escapement, with jewelled pallets and mercurial compensation-pendulum, the usual means for altering the length of the rod and putting it in beat, and an index attached to the base of the stirrup that supports the mercurial cylinder, which indicates the arc of vibration upon a divided scale secured to the back of the case. Its pendulum index has been wrought to a delicate knife-edge, which at every vibration passes, as suggested by Saxton, through a globule of mercury supported on a slender bracket projecting from the divided scale. There are wires leading to a galvanic battery and register, for the record of observations upon a Morse fillet.

"The other clock was designed by Dr. Locke, made by Messrs. Howard & Davis, and put up in 1850. It is secured to the west face of the pier originally intended for the Mural Circle.

"The Mural Circle is in the east wing. It is five feet in diameter, and is mounted upon the east face of a sandstone pier. It has a conical axis three feet long, with friction-rollers under the eastern end, connected with rods which pass between the circle and face of the pier, and thence Over the top to counterpoises within the cavity of the pier.

"The circle and radial bars, twelve in number, are part of the same casting. The latter are strengthened on their backs by edge bars, and united midway by a second concentric circle. It is divided into 5' spaces upon a band of gold, inlaid upon the rim perpendicular to its plane, and into whole degrees upon a platina band near the gold one. Each of the latter is numbered. The reading is by six equidistant microscopes secured to the face of the pier, and illuminated through apertures in the same by a gas lamp west of it. The telescope is a cylinder, secured to the circle both at the centre and at the extremities. Its object-glass is four inches in diameter and five feet in focal length. Troughton & Simms were the

makers.

"In the same room, and east of the Mural Cirde, is the Meridian Circle, an instrument origi nally made by Ertel & Son, and remodelled and furnished with new circles by Mr. Wm. J. Young, of Philadelphia. The material changes, from the description of it given in the volume of Observations for 1846, are the substitution of circles forty inches in diameter for the defective ones of thirty Inches, and the removal of the clamp from one of the circles to the axis.

The clock in this room is placed south of, and equidistant from, the two circles. It was made by Mr. Chas. Frodsham, of London, and is similar in its construction to that of the west wing. But, instead of the single knife-edge, its pendulum

which at each vibration impinge simultaneously upon globules of mercury in separate receptacles of the bracket, whereby the galvanic circuit is closed without passing it through the pendulum. A recording apparatus has been arranged for tho instruments of this room. "The other room of the east wing is wholly de voted to nautical and other instruments for naval purposes. Cases to contain the chronometers, and shelves, &c., are so disposed as to accommodate the largest number and facilitate their examination or distribution. The clock used in rating the chronometers was made for the old Depot of Charts and Instruments by Messrs. Parkinson & Frodsham, and is similar to that of the west wing. It is mounted upon a granite pier, in the southwest corner of the room, and, except the Kessels' clock, its performance is more satisfactory than that of any other one belonging to the esta blishment. To facilitate and render more certain the comparison of chronometers when noise renders the beat inaudible, it is provided with an electro-magnetic battery, connected by wires with a heavy-sounding tiit-hammer placed near the chronometer cases, which strikes seconds audibly at each impact of its pendulum index with the mercury globule.

"The Transit in the prime vertical is in the north room of the south wing. The telescope has an aperture of 4.85 inches, and a focal length of seventy-eight inches. It is attached to one extremity of an axis forty-two inches long, the other extremity carrying a counterpoise. The pivots of the axis are of fine steel, 3.5 inches in diameter, and are hollow. The telescope and its counterpoise are outside of the supporting pier, but their weights are transferred to the bearing points of the Ys by levers and other counterpoises within the pivots and axis. Its pier is a wide monolith, whose central portion has been cut out for the ac commodation of a reversing apparatus of special construction.

"The instrument has not been in use for seve ral years, and such had been its neglect that it was necessary to dismount and grind out the oxidation of its pivots and make other extensive repairs. These were very successfully performed by Mr. William Wurdemann and the machinist. of the Observatory, and observations in the prime vertical are now made.

"The clock was made by Charles Frodsham, and is mounted against a granite pier placed east of the prime vertical transit instrument. Instead of glass, it has a steel cylinder for the mercury of its pendulum, and the pendulum-rod screws into a cap covering the upper part of it. The pendulum index has a single knife-edge, like the clock of the west wing.

"The other room of the south wing is in use for library purposes, the piers erected in 1846 for an instrument of unsuccessful design having been removed.

"The Equatorial Instrument under the dome is mounted upon a massive granite pedestal, which rests upon a hollow conical pier whose foundation is nine feet below the ground-line. The instrument was made by Messrs. Merz & Mahler, with an object-glass of 9.6 inches, and focal length of ourteen feet three inches. The finder has an object-glass of 2.6 inches diameter, and focal length of thirty-two inches. The hour and declination circles are, respectively, fifteen and twenty-one inches in diameter. The telescope may be kept

in motion by clock-work, and differential measures are made with a micrometer microscope, constructed from a design by the same distinguished optician. The instants of observation are recorded by chronographic apparatus connected with the clock in the south wing.

"A comet-seeker, made by Messrs. Merz & Mahler, stands within the rotunda when not in use. It has an object glass of 3.9 inches aperture, and thirty-two inches focal length, and eye-pieces with magnifying powers ranging from twelve to fifty times. It is equatorially mounted on a shaft of brass supported upon a tripod having the ordinary adjusting screws, and has hour and declination circles each of five inches diameter, whose divisions read by means of verniers to 1'. Its telescope is of deal, with a veneering of mahogany. It is accurately balanced in every position.

"There are substantial supports outside the rotunda, from one or the other of which all portions of the heavens may be seen, and a level platform covers the roof of the building for the greater convenience of the observer with the cometseeker.

"For the purpose of giving correct time to the city, a staff has been placed on top of the dome, and a large but light ball is hoisted ten minutes before twelve o'clock of each day except Sunday. The pulley is connected with an electro-magnetic battery after the ball is up, and the circuit is broken by the assistant in the chronometer-room at the instant of noon."

The charts and nautical books are arranged in two rooms and the hall of the second story. They are under charge of Commander Whiting and

Professor Pendleton, U.S.N. Each chart has its number, and all are arranged so as to promote the most expeditious and safe selection. More than 20,000 sheets per year have been distributed since 1861.

The chronometers and nautical instruments are in the east room of the east wing. They are under charge of Mr. John R. Eastman, Aid, who compares all chronometers at noon with the star dard clock, makes up rates of those on hand at the end of each month, and selects the instru ments for vessels to be equipped. He is responsible for the workshop, where all instruments returned from vessels and needing repairs are put in order, and thus a great saving to the Government is annually effected. Mr. Clark, a most thorough mechanician, is kept constantly employed on these repairs and incidental injuries to the astronomical instruments. He has one laborer to assist him.

As a matter of popular information for the benefit of those who read and wonder at the accounts of astronomical observations which record the movements of the heavenly bodies to the hundredth part of a second of time, we extract from a pamphlet issued by one of our colleges the following description of the instrument and the method by which that wonder is performed.

The elegant instrument of Prof. W. C. Bond, known as the "Magnetic Register," or "Spring Governor," is one, by and upon which, through the influence of electro-magnetism, the instant of time at which an observation takes place can be precisely recorded. By means of very delicate machinery regulated by the "Spring Governor," a contrivance at once peculiar and beautiful, a horizontal cylinder, thirteen inches long and six in diameter, is made to revolve with great uniformity, precisely once per minute of sidereal time. Around this cylinder is clamped a sheet of paper; and upon this rests a glass pen filled with ink, which, as the cylinder turns from under it, inarks a line from end to end of the sheet. This line, in length, is the exact measure of the duration of one minute of time. Upon the opposite end of a delicate lever, to which the glass pen is attached, is a small vertical iron bar, known as an "armature," resting close in front of, but not in contact with, the "poles" of a soft iron norseshoe magnet. This magnet is coiled with wire, and is in the circuit of a galvanic battery,

which circuit is also, by an ingenious arrangement, made to pass through a fine steel spring, dipping into a globule of quicksilver directly be neath the pendulum of a sidereal clock. Attached to the lower extremity of the pendulum is a small ivory index, which, at every vibration, drives the little spring out of the mercury, but instantly on passing, allows it to return. In this manner the circuit is almost instantaneously broken and closed, at the termination of each second of time; and this "break" and "make" of circuit are at once answered by the pen, in obedience to the action or rest of the magnet with which it is connected, thus dotting upon the sheet, as it revolves, the sixty seconds constituting the minute of its revolution. The movement of the "armature" from the magnet during the instantaneous release of the latter from the influence of the galvanic circuit, is effected by a little bow spring; and, in order that the pen shall not return upon the lines already described, the whole magnet is moved forward on a miniature railway, by means of a cord passing round the axle of one of the main wheels of the "Spring Governor." By means of this instrument and a "break circuit" key, always near his hand, the observer, by simply touching a delicate spring, is enabled to record with the utmost degree of precision in among the second marks of the clock, the time of any ohservation he may wish to obtain, to the hundredth part of a second.