US82984A

US82984A - Improvement in meridian-time indicator

Info

Publication number: US82984A
Authority: US
Publication date: 1868-10-13
Anticipated expiration: 1885-10-13

Description

E. PREVEAR.

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EDWARD PREVEAR, OF LEOMINSTER, MASSACHUSETTS.

Lettersllateat No. 82,984, datetlOctober 13, 1868.

The Schedule referred to in these Letters Patent and making part of the same.

To all Vwhom it may concern'.-

Be it known that I, EDWARD PRE man, of Leominster, in the county of Worcester, and State of Massachusetts, haveA .invented and iliade a certain new and useful improved Meridian-Time Indicator; and I do hereby declare the following to be a full, clear, and exact description of the saine, reference being had to the annexed drawing, making part of this speciiication, wherein- Figure 1 is a vertical section of my apparatus, and

Figure 2 is a plan of' the same.

Similar marks of reference denote the same parts.

This invention Yconsists in an instrument for indicat- .ing meridian time with great accuracy. It is portable,

and not liable to injury either from exposure or in handling, and the apparatus is adapted to use at any? season of the year, regardless ofthe suns declination.

This invention consists in a fixed bed-plate, formed with bearings to receive a swinging meridian-'arm and lens. The hed-plate is to he attached to a lirm post or other support, so that the bearings for the arm stand east and west, in order 'that the aiin'may be swung in the plane of the meridian, to accommodate the position of the sun or of any star when crossing the meridian, and thereby determine accurately the time by moving said arm, so that a shadow or reflection is cast on an index on the meridian-arm. The

meridian-arm, when not in use, may be detached from the plate and properly housed.

ln the drawing, a represents the top of a post or other firm support, to which the bed b is attached by suitable screws, c, or other means, and adj usting-screws may be employed as at d; and upon the plate o r bed b are bearings c c, for the journals f of the meridianarm g.

The bearings e c are made forked, so that the journals f can be removed easily or set into their places, and pins, h, may be introduced over the `iournals, to keep them in place, but allow the arm g to be raised or lowered at its outer end, so as to come on hne with the sini or other body crossing the plane of the ineii'dian.

I employ. a lens at i, through which thev rays of light pass, and the focus thereof is the index k, that is divided intominutes to the sides of the nonius, so that the` observation can be made a few minutes before or after the body crosses the meridian.' v

It will be understood that the arm g, swinging m the plane of the meridian, will indicate correctly meridian time, and will be a great convenience for determining accurately the time of day under circumstances Where the true time cannot be easily obtained by other