USRE11475E - Instrument for taking nautical observations - Google Patents

Description

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N O. 11,475. l ReiSSued'Feb. 26, 1.895.`

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f w. H.l BBEHLBR. INSTRUMENTPOR'TAKING' NAUTIGANL OBSERVATIONS. I

No. 11,475. -Reissued Peb. 26, 1895.

VVitnesseS:

Attorneys.

UNrTED STAT-Es PATENT ,Orrin-a.

WILLIAM BEEHLER, OF'JTHE UNITED STATES NAVY, ASSIGNOR TO THE BEEHLER SOLAROMETER COMPANY, OF BALTIMORE.MARYLAN D.

INSTRUMENT FOR TAKING NAUTlCAL-OBSERVA'TIONS.

SPECIFICATION forming part of Reissued Letters Patent No. 11,475, dated February 26, 1.895. Original No. 464,261, dated December l, 1891. Application for reissue filed November 15,1894. VSerial No. 528,932.

.Taall'whom/.it may concern.-

Be it known Vthat I, WILLIAM H. BEEHLER, a citizen of the United States, residing in the city of Baltimore, StateA of' Maryland, have Sull.

invented an mprovement in Instruments vfor Taking Nautical Observations; and .I hereby declare the following to be a full, clear, and exact description of the same.

My `invention relates to an instrument for taking observations ofcelestial bodies, and solving problems in practicalautical astronomy without reference to the sea horizon.

It consists in certain features which will be more clearly explained by reference to the accompanying" drawings, in which the same parts are indicated by the -same letters lthroughout the several views.

Figure 1 is aside elevation of my apparatus.

` Fig 2 L isa view taken at right angles with Fig. A1, and showing part of thel artificial horizon,

declination, and meridian rings. Fig. 8 is a` crosssection of a telescope for observing the Fig. 4 shows a modification of my device. Fig. 5 is a plan view of the apparatus. Fig. 6 is an enlarged side view of a section of the post R and the ring B, showing the operating devices. Fig. 7 is a transverse sectiony of the same. Figs. 8` and 9 are enlarged details of thetelescopes or observing-tubes and their connections. Figs. 10, 11, and l2 are enlarged details of the equatorial and declination rings at their points of. junction, showing also the verniers. Figs. 13 and 14 are enlarged details of the supplemental azimuth and declination rings.'

'Tlhel instrumentis 4called a solarometer,

meaning an instrument to measure with the sun, though it is used for observations of the sun and stars. Ordinarily when starsare observed the position of the star is referred to that of the sun and the observers 'position determined by comparing the hour angle as vobserved by the instrument' with the' mean time'indicated by the chronometer regulated to Greenwich mean time. l The said instru mentconsists essentially of a plurality of angularly adjustable concentric rings mounted upon a floating base piece and hence kep-t ata constant level.

H is a graduated ring supported upon the brackets C whiehhf.e their lower ends atgation of the axis of the rod R.

tached toiand supported by the rod or post R carriedby the float F. Y This ring H is placedat right angles to the vertical axis of the float and is hence supported so that itis constantly evel and is therefore an artificial horizon, and the center of this ring is in the prolon This ring may be fitted with spirit-level bulbs H', countersunk in itsface to indicate any deviation 6o from the true level but these are not necessary, andfserve only as a check on the leveling of the instrument. The rod R projects vertically upward from a `float F', which is supported in mercury contained in a bowl K.

This bowl is supported by gmbals upon the upper end of an upright post or pillar which is secured to the deck of the vessel, aud'by these meansthe motion of the vessel is prevented from communicating itself to the ap- 7o paratus, which is supported upon the deck. The bowl K is ordinarily made spherical to a point about two-thirds of its diameter; the

vupper one-third being cut away to form. an opening ormouth whose edges terminate in a short vertical cylindrical extension with a flat rim or lip. The floatis ordinarily heinii vspherical in the'upper portion and has a dat circular` bottoni with re-entering curved edges, and, with its Asuperincumbent weight, 8o

its displacement of mercury is such that when the' bowl is level the flat surface of the bottom of the float'lies below-the hori- `zontal central plane ot' the hemisphere and parallel therewith. Rings q upon the outer surface of the iioat and q' and q2 upon the 'innersurface of the bowl arranged above and below the center, limit-the inclination of the oat'with respect to the horizontal central plane ofthe bowl. the short cylindrical extension at the mouth of the bowl, constitute a fermeture to keep the mercury ill the bowl in case of extraordinary violent heeling ofthe ship. It' this. should occurto such an extent as to these rings into contact, no reliable lobserva- 'tion could beI taken with the apparatus, be-` causeit would not be perfectly level.` The greater portion of the heeling effects caused by the motion of the ship is annulled by having roo the apparatus secured amidships and by the gimbal-supports of the spherical bowl.. The

These rings, together with 9o.

bring ring B has the center of its curvature in the exact vertical line of the prolongation of the axis of the rod R. This center i-s also the common center of the entire system of dependent rings. This ring B is graduated into degrees and fractions from zero to ninety degrees upon each side, as shown in Figs. l and 6. It fits into a slot iu the top of the rod R and has its `interior curved edge formed into ratchetteeth, which are engaged by a pinion B', as shown'in Figs. 6 and 7. -This pinion is mounted upon a shaft extending through the slotted upper end of the rod- R and having disks BO upon the outer ends, so that by turning these disks and shaft, the pinion vwhich engages the ratchet-teeth, will act to move the ring B in one direction or the other within the slot, and thus either-pole of the sphere may be elevated while the other is correspondingly depressed. The lower outer edge of the ring B has a slot made in it which forms a keyway or guide for a rib which projects upwardly from the bottom of the slot in the rod vR, as shown at B2, Fig. 7. Near the extremities of the ring B', this slot is cut entirely through the ring,and the pins A and A which extend lar bracket, as shown at P.

' constellations.

under the horizon-ring H, as shown in Fig. l', have their ends entering into this open slot. By this construction the ringr B is held so that the axis of the poles P lies in a plane passing through the zero-points of the graduated hori-V zon-ring H. A set-screw B3 tits into the side ofthe rod R, and by this means the ring B may be clamped in any position to which it has been moved by aid of the thumb-'screws and pinion B', as before described. f f

S is a sphere of any suitable light material, having upon. its surface a graphicalrepresentation of the fixed stars and the different It may have also meridianlines, equator, and parallels and ,the ecliptic also may he marked upon its surface. This sphere is supported to revolve with the polar axis having bearings at each end in the po- This sphere performs, however, only the functions of a star chart or a stellar globe, and in no way aiects the operation of the instrument. fIt may be omitted altogether-if desired.

M M is a ring, which is a narrow segment of a sphere concentric with the various rings.

. It is supported upon the polar axis P P and is free to revolve thereon. This ring is called the meridian-ring, and may beswung through any angle about the' polar axis 'P P. It has --beyond it.

a longitudinal slot in tlie center of its outer surface, and one ot the pins A which project beneath th horizon-ring H and engage the slot in the polar bracket B, also enters the slot in the ring M. lower end of the bent arm W, depending from the azimuth circle Z, to be hereinafter described, also enters the slot in the ring M, and these pins serve to connue the meridianring M in such a position that the vertical planeof the center of its-longitudinal slot occupies the position of the observers local meridian when theinstrument isin the proper position for taking observations. The slot in the meridian-ring and that in the outer ends of the polar bracket B are inthe same plane. The slot in the polar bracket is cut through at sixty-five degrees from each pole toenable the pins A to pass through it and into the slot in 'themeridian-ring when the pole is elevated. l

In practice it will not be necessary, as a rule, to use the instrument in latitudes above sixty-five degrees north or south, and'this is the reason for` `limiting the slot to that distance. VVhenthe observeris in zero latitude, or when the polaiaxis' lies in the plane of the horizon-ring H, the pin A will pass through the slot in the bracket B near the polar. axis; but as the -pin is below the ring H the thickness of this ring carries the pin sufficiently below the polar axis to prevent its interfering with it in that direction. l

E isv the equatorial ring. This is also a narrow segment of a sphere concentric with the various rings and isof slightly greater diameter than the meridian-ring M. This ring E is rigidly attached to the meridianl ring at right-angles to it.. Braces M' connect The pin w at thev roo the two circles and serve to rigidly support y the equatorial ring in a plane at right angles to that of the meridian-ring M, as shown *plainly in Fig. 5. The outer surface of the ring E has a knife-edge` rib e which projectsr This knife-edge occupies the exact plane of the great circle perpendicular to the plane of a great circle passing through the poles P P. The outer surface of the equa` torial ring E is graduated into twentyLfour hours, and thehours into minutes, and seconds of'ti'me, with the zero andtwelve-hour marks at its point of intersectionwith the meridian-ring M. On opposite sides ot' the IIO equatorial ring E are grooves E2 for bearingt surfaces` for the declination-ring D, (shown plainly in Fig. l2.)

The declination-ringD is a narrow segment ot' a concentric'sphere, and of the same diameter as the edge of the rib upon theequatorial ring before described. This declination-ring is supported upon the polar axis P, around which it is free to revolve over the surface of the sphere and over the meridian-ring M. Its middle portion, at ninety degrees from the pole, is cut and formed to fit into the `grooves E in the opposite surfaces of the equatorial ring, and elevated T rails or ribs D project- .ing above its surface connect the two parts the equatorial ring E to ninety degrees at thev poles. The ribs or rails D' are upon .each side of this slot, and extend continuously from pole to pole, connecting the two parts of the y ring where separated by the projection of the knife-ed ge of the ring E, as before described.

`T ese ribs or rails serve to support the declin'atiomvernierwhich is shown in Figs. l0. and 11.

which travels on these rails'D.

This vernier isY fitted in'v a frame .Thegraduations of the Vernier arc on one side of the center line are opposite the graduations of the declination-ring under the frame 'and' which showy through.

l tn beT on the azimuth arc Z -Z are la. pinD, which is At the initial point of the vernie'r there is perpendicular to the tangenbplane of the arcD at this point. This pin carrie`a`ball=socket at its outer end, and

this receives a ball dpendentat the end'of the pin ZP, as shown in Figs. l 'idrfwhich .hangs down from the center of the mirror on`` -theazimuth arc Z. The pin ZP and the pin Da and the axis of the telescope or objectin a straight line Yfrom the common center of the circles.

The Vernier-block D and the tangent-block D4 have T-shaped grooves made in their lower .surfaces to fit the T-rails D', and a set-screw y Ds clamps the block D tothe surface of the .I declination arc D. The tangentscrew Dt brings the vernienblock D8 to anydesired position by accurate coincidence with graduaons of 'the declination arc D and those of the Vernier-scale.A VThetangent screw Dt is supported in movable posts i.

` joints upon upright 4These movable joints are screw threaded, forming nutsthrough whichA the screw turns, and by their movement the screw will act in the direction of a tangent, while the Vernier-block moves over the curved surface' of the declination arc, this being the general construction of verniers as tted to sextants. At one side of the declination-ringD there is another Vernier and Vernier set-block E', which works on the equatorial ring in a similar manner, asfshown in Fig. 10. This f marks the accurate adiustmentof the declina- 5S tion are D to the position where it is desired to clamp itor Where it may be brought by its junction with the azimuth arc when observing Aa celestial body'.

It will be understood that all of the verniers with set-blocks and set-screws' and tangent-screws are arranged similarly to that above described to allow a movement of the parts while the screw acts in the direction of the tangent. r

The azimuth and altitude rin'g'Z is a narrow segment of a sphere of the same diameter as t/he ring l-I. It is supported vertically upon the ring H and is free to revolve about a vertical axis around a zenit hpin which is fixed to the zenith of the ring in the exact prolongationof the axis of the rodR and in the vertical line above the center of the system of rings. Shoulder-.pieces Z extend horizontally from the feet or ends of the ring Z a-nd iit upon the ring H; These yfeet of the ringZ are enlarged and slide over the fiatsurface ofthe ring H. On one foot is a Vernierscale withA a tangent andset-screws, as shown at Z3, by which the exact position of the imaginary vertical circle Z can be read by the graduations on the ring H.' One edge of the Figs. 5 and 8, so that the exact vertical circle' through the zenith to the horizon will pass shown by the dotted lines in Fig. 5. Upon this azimuth arc Z is supported-a sliding carriage T', upon which are'mounted two tubes or telescopes O and T. The axis of the telescope T is supported upon this sliding carriage in such a position that it is in a vertical plane passing through the common center ofthe circles. The carriage supports a box T2 directly beneath the telescope T, and this box icontainsigl mirror T3, xed at ailangle with the plane ofthe-tangent ofthe arc Zwin such a manner that the surface f the mirror makes 'equal angles with the axis of the telescopes Tand 0./

Attached to the box Tzand directly in prolongation of the axis ofthe telescope T is the dependent pin ZP, having theballjoint which connects it with the pin D2, as previously described. A l

When the telescope T is turned toward a celestial body the image of that body is reliected by the mirror TS and will be seen in the axis of the tube O. the mirror T3 where the axis of the telescope meets the mirror is marked by the intersection of crosslines on the mirror. The lenses in ther telescopes T and O focus the image of the body observed on the mirror.A

i In order to obviate the lossof light, to dispense withv lenses, and to secure au observation of the center ofV the sun, moon, or other body and bring it accurately to the center of the observing-tube, I substitute for the telescopes T and .O two tubes, which a`re`providcd with sliding leaves or shutters having central holes, so that bythe use of any of these shutters the aperture may be reduced to as small a diameter as may be necessary for. the purpose. These sliding leaves or shutters are plainly shown in Figs. t5 and U at T4. They are hinged on one side, so that they may turn into or out of slots madein the side of the tube. W'hen turned in to the-full extent, the center of the leaf occupies the exact line ot' the axis of its tube. leaf iS provided with two cross-hairs, made oi flue platinum wire. These Wiresintersect or join a central circle ol' preferably about one millimeterin diameter, outside measurement.

ring Z is cut away or recessed, as shown in through this space to one side'of the ring Z, as-

The exact point on l The ceuterapertnre ofthe sliding Ico The wire is also joined'toase'cond concentric ring, as shown in Fig. 9.. The four sliding lea'ves t in slots near the ends of the tubes T and O, one in each end of each of the tubes. The mirror is plain, without any marks, and the reflection is such that when all four of the sliding leaves are pushed into the tubes the cross-Wires and rings all coincide with the shadow reflected from the mirror. If the sun be observed, its disk will appear to occupy almost the entire aperture. Vhen the axis of the tube isin the exact. direction of the center of the sun, the suns disk will appear to be symmetrical with that of the shadow caused by the outer platinum-wire ring. vIt the moon be observed, its center will be in the axis of the tube T, when the curvature of the visible disk is seen to coincide symmetrically with that of the outer wire ring Lof the sliding. leaf. If a star be observed, it will be in the direction of the axis of the tube,when the star appears to be exactly in a central inner wire ring. Theshadows of the platinum wires enable observations to be taken of heavenly bodies when exactly in thedrection of the axis of the tuhe-'-that is, in4 a line to the center of the system-or practically as-if observed at the center of the earth.

In making observations of stars the sliding leaves are pushed out, so that the entire aper- Ature of the tubes will be clear to [ind the star with facility. When the azimuth arc is turned so near that the heavenly body is seen'in the tube, it becomes necessary to make kfurther adjustment to bring the bodyin the axis of the tubes. The sliding leavesv T1 are then pushed into the tubes and the several arcs D, E, Z, and B are turned by their tangentscrews until the body observed appears ex-Y actly in the axis of the tubes. These tubes will only be in that position for about one second of time, and it is necessary to turn the tangent-screws on E and Z accordingly to get the exact instant when the star or the center of the sun or moon is in the axis of the tubes. That instant is noted by the chronometer or watch regulated to Greenwich apparent time. The diierence between this apparent time and the local hour-angle read off on the equatorial ring between the arcs D and M gives the longitude. In case of observations of the sun the hour-angle is local apparent time.

If observing a star, planet, or the moon, the

- local apparent time is obtained by reducingr the hour-angle of the body, as observed, to that of the sun by applying the algebraic difference of the right aseensions of the sun and body observed, as given in the Nautical AZ- manac. There is no difficulty in making final adjustment with the tangent-screws on the arcs E, Z, and'B. Since the declination of heavenly bodies changes very slowly, it does not require much manipulation to bring the body in position above orbehiud the center ofthe cross-wires. One or two turns of the ratchet-pinion B' moves the arc B so as to bring the tubes to the necessary elevation,

which does not change in the few moments of time necessary to take observation. The tangent-screw of D on E is the only one necessary to follow the body except it be a body which changesits azimuth very rapidly, when it is also necessary to move the tangentscrews of Z on the ring II. A

In order to automatically make allowance for the eifect of the refraction of the atmosphere, the curvature of the ring or are Z is not strictly that of a segment of a sphere, but diiers slightly in the shape of its outer surface.

The refraction of light is greatest when the heavenly body is at a low altitude. lVhen in the zenith,the effect of refraction is nothing.4 The tube or telescope onl the arc Z is therefore caused to move over an arc whose curvature changes by the amount of refraction, this curvature being produced by making the outer surface of the arc Z the curve of a circie with a constantly-changing center.y This arc is constructed in accordance with the known amount of refraction which has already been calculated andcompensates this refraction so that the true altitude of the body is indicated instead of its apparent altitude. I have calculated this compensation for an atmosphere at a ltemperature of 60 Fahrenheit and barometer thirty inches. At greater or less temperature and at different pressures there are Varying effects of refraction, but this variation under Aabnormal conditions is chieiy at low altitudes. These low altitudes are to be avoided, not only on account of refraction, but chiefly because the instrument is located on board the ship low down, so that the rail vwill often render it impracticable to observe heavenly bodies at low altitudes.

Z2 is an adjustable weight movable upon the azimuth-ring and fixed thereto at a point yon the opposite side of the zenith-line from the telescope-carriage, so as to counterbalance vthe latter and maintain the horizon-ring at an exact'level. I

When the instrument is used for finding Greenwich mean time from lunar distances,

an additional declination-ring and azimuthring are employed. These rings are ittedin all respects like `the declination-ring D andazimuth-ring Z, with mirror, telescope, ob-

serving-tube and other parts, as hereinbefore described. The arc Za is in all respects similar to the azimuth arc Z except that it is of greater diameter near' the zenith, whereit is enlarged to fit over the arc Z, as shownjn Fig. 13. The bent arm W on the arc Z, which carries the pin in the exact plane of the azi-V muth,`i s provided with an extra piece, which carries an arm over the top of the are Z and which fits into a slot in the highest point of the arc Z. This arc Za rests upon the horizon-ring and has a Vernier with set and tangent serews in all respects like the azimuth arc Z. The adjustable declination arc D is fitted with forked ends to fit onto the polar axis P on each side of the bearings of the permanent declination-ring D, as shownin Fig.`

14. It is of the same diameter as the ring D, except at its ends and it is only one hundred and eighty degrees in length from pole to pole. It has a central slot with graduations and a Vernier-scale with pin-and-ball socket N to receive the dependent pin Zp from the arc Za.

When adjusted, the arcs Za and Dqd are employed for observations of the heavenly body exactly like those of Z and D, of which they are practically duplicates in essential features. They afford means by which two observers may simultaneously take observations of two heavenly bodies visible in the heavens at the same time and not too remote from each other. Such observation indicates the lunar distance, which is measured on a graduated metal tape-line.

The distance between the verniers at the initial points on D and Da, measured on this graduated line, is the angular apparent lunar distance between the two bodies, the moon being observed on the arc Z and the sun or star at the same time on the arc Z.

TheNautcalAlmanac gives the lunar distance of heavenly bodies, andby comparing the lunar distance observed with that of the almanac the exact Green wich time is obtained at the instant of observation. It the instant of observation is noted by a chronometer, the error of that chronometer in the Greenwich timeis the difference between'the time shown by the chronometer andthe exact Greenwich time, and is thus ascertained from the lunar distance. The local time is found from either or both of the hour-angles made by ei'therD or D with the meridian-ring N. It both hourangles give the same result, it is a check upon the accuracy of the observation.

In taking an observation of a lunar distance it mustbe done with the moon at such adistance from the other celestial bodythat either one or the other is at some distance from the zenith, so that theV slidingr carriages-on the two azimuth arcs will not be so close together as to interfere with each other.

An upright standard is fixed in front of the solarometer in line with the keel and has an index'U hinged to it, so as to rest slightly upon the edge of the horizon-ring H, and this will indicate the exact direction of the ves- Vsels head at the instant of any observation,

from which the compass error may be obtained.

Having thus describedmyinvention, what I claim as new, and desire to secure by Letters Patent, is

1. In an apparatus of the character described, the combination with a bowl suspended from gimbals and partly filled with a heavy liquid, a-tlat floating in the liquid in said bow1,'a vertical column carried by said float, and apparatus for taking observations carried by said column, substantially as described.

2.7111 an apparatus of the character described, tliecom-bination with a bowl sus pended from gimbals andpartly filled with a heavy liquid, of a Iioat fioating in the liquid in said bowl, a vertical column' carried by said float a horizontal circle carried by said column, and a pointer adapted to indicate the bearing ofthe ships head relative to said horiy zon circle, substantially as `described.

3. The combination with a vessel containing liquid, of a movable float therein, a graduated circle attached to andcarried by said oat parallel to the surface of said liquid, and means for ascertaining the bearing of any given diameter of said circle, substantially as,h 8c

described.

4. The combination with a vessel containing liquid, ofa movable float therein,agr adu ated circle attached to and carried Aby said iioat parallel to the surface of said liquid, and a pointer secured in a fixed direction for indicating the bearing of any given diameter of said circle, substantially as described.

5. In an apparatus of' the character described, the combination with a vertical column and means for keeping the axis of the sameyin a vertical position, of the telescope carrying arc supported on said column, the

telescope adapted to slide along said arc, themirror, and object'glass moving with said telescope, anda plurality of/circles concentric with each other for indicating the latitude, declination, and described. y

6. In an apparatus of the character described, the combination with a oat and a vertical column carried thereby, of a telescope carrying arc pivotal'ly mounted on said column the telescope, mirror, and object glass secured .together and adapted to be moved hour-angle, substantially as IOC along, said telescope carrying arc; a declinal tion circle anda movable connection between said telescope and said declination circle, and

an equatorial circle, meridian circle and polar 4 bracket concentric with said declination circle and mounted on said column, substantially as described.

7. An apparatus for taking nant-ical observations comprisinga bracket, graduated rings or circles, concentric with each other and carried by said bracket, a floating base or support and a mirror mounted upon one of'said ci rcles,and interrupting the line of sight `te the center thereof, whereby an observation of celestial bodies is taken as if from the exact center of the earth, substantially asI described.

8. An apparatus for taking nautical observations comprising concentric graduated rings, and spherical segments having a common center therewith,a liqnidcontaining' bowl with gimbals upon which it is supported, and a float supported in the liquid and upon which the segments, and circles are adjustv ably supported, whereby observations at sea may be taken independent of the 'visibility ot the sea-horizon, substantially as described.

9. In an apparatus of the character described, the combination of "concentric rings in segments of concentric'snheres of dieren't vations comprising a bowl containing mercury, a fioat resting in said mercury and forming a constantly-level base, a post or support extendingupwardly from said float, a bracket.

carried thereon, a horizon circle supported upon'said bracket, an adjustable polar bracket, and the meridian azimuth, and altitude rings arranged concentric with each other and mounted upon said float, substantially as described.

11. An apparatus for taking nauticalobservations comprising the suspended bowl containing mercury and the'tloat restin",r therein, the adjustable polar bracket, the horizon, meridian, and declination. rings and the azimuth-ring the curvature of which varies from that of a circle, so that as the sliding,r carriage of the telescope-mount is moved upon the azimuthring the axisof the telescope will be adjusted to correct 'for the refraction of the atmosphere, substantially as described.

12. An apparatus offthe character described comprising the suspended bowl and tloat,the adjustable polar bracket, the azimuth-ring,a sliding carriage moving,r thereon and carrying a telescope, in combination with an inner'tube having thc same axis with the telescope, andv the concentric band adapted 'to throw shadows .of concentric circles upon the'mirror when a celestial body is observed having a visible diameter and for the purpose of adjusting the telescope to the exact center of said body, substantially as described.

13. In an apparatus of the character de scribed the combination with the suspended bowl and float, the horizon-ring,` supported therefrom, of the adjustable polar bracket, the azimuth circle, with the movable carriage, telescope, and observing-tube and mirror supported at the junction of the axis of theY observing-tube and telescope, the declinationring having a Vernier-scale, and a flexible connection beneath the mirror-inthc vertical plane, through the common center,of the circles, substantially as' described.

14. An apparatus for taking nautical oUs'ervations comprising a bowl suspended upon gimbals and containing mercury, a float adapted to rest in the mercury in said bowl,

a polar bracket supported 'by and adjustable from said float, horizon and meridian circles,

and an azimuth-ring,arianged concentric with each other, a mirror, a sliding carriage adjustable upon the azimuth-ring,a telescope mounted upou-said carriage, and au observing-tube mounted upon the same carriage and with such relation to the telescope as to cause the lines of the axes of the telescope and observing-tube to meet the surface of themrror at equal angles, substantially as described.

15. The graduated rings and circles, and a horizontal ring supported upon a float so as to form a constant level base, in combination with the hinged index-hand attached td avertical support in the vertical plane of thekeel of a vessel, and in front of said apparatus, whereby the bearing of the ships head may be indicated by the graduations upon the horizon-ring of the apparatus at the instant of anyobservation, substantially as described.

"In testimony whereof I have hereunto aixetl my signature in the presence ot` two subscribing witnesses.

Y VILLIAM H. BEEHLER. W'tnesses:

J oHN CHALMERS WILSON, vlvIAUrnori J. SIoUssA.

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