US281527A

US281527A - Sun-dial

Info

Publication number: US281527A
Authority: US
Publication date: 1883-07-17
Anticipated expiration: 1900-07-17

Description

(No Model.) I 2 Sheets- -Sheet 2.

N LARSEN.

SUN DIAL.

No. 281,527. BgjltfhtBd July' 17, 1883.

WITNESSES? I INVENTOR;

i'g m' a 7 .BY ATTORNEYS.

' UNITED STATES PATENT OFFICE.

NIELS LARSEN, OF WEST POINT, NEBRASKA.

SUN -DIAL.

SPECIFICATION forming part of Letters Patent No. 281,527, dated July 17, 18 83.

Application filed March 17, 1883. (No model.)

a the globe upon which the shadow of a ball located at the earths center would travel, supposing the earth to be transparent, arranged in connection with a ball and an adjusting device, and having longitudinal lines of declination and transverse lines for hour-marks, mak- .ing a simple and efficient sun-dial or solar compass, all ashereinafter fully described. Reference is to be had to the accompanying drawings, forming part of this specificatiomin which similar letters of reference indicate corresponding parts in all the figures.

Figure 1 is a perspective view of my improved sun-dial. Fig. 2 is a diagram illustrative of the principle of the invention. Fig. 3

is a perspective view of a dial constructed according to my invention with a modified arrangement for adjusting it for latitude and a modified arrangement for supporting the ball.

Fig. 4 is a perspective View of a dial con- Supposing the earth to be a transparent globe,

with a ball placed in the center, then the shadow of the ball would travel around the globe once in twenty-four hours; and if the sun s declination was south, say, 10, the shadow of the ball would travel 10 north of the equator. If we then take that portion of a globe lying 2328 on each side of the equator, the extent of the suns declination, with a ball in the center and the upper half cut away, it would form a I semicircular ring, on which, if suspended parallel to the equator, the shadow of the ball would travel as on the earth. If we make the ring flat, it will be the tangent of a globe of the rings diameter, as shown in Fig. 2, and if tangent lines of declination are drawn on this semicircular ring, with a ball suspended in the center, the shadow of the ball will travel along the line of declination all day if the ring is suspended parallel to the equator-that is, with an angle from the vertical equal to the latitude of the place. I

In the drawings, a represents such a semicircular ring as abovedescribed, which may be suspended on pivots b, supported by any suitable uprights, c, with an adjustable .arc, d, for settingit for latitude; or it may be suspended by chains 6 with an adjusting-screw, f, foruse instead of the are d. V

9 represents the ball to be set in the center of the ring for casting the shadow, said ball to be supported by a thread, h, regulated by screws n, or any other approved means. For example, in a simple and cheap'devioe to be carried in the pocket, a frame, 1', may be used, said frame being mounted on a bottom, 9', to be attached to the ring. The said frame may be so constructed as to be lowered down and raised up, as may be required.

k represents the line along which the shadow of the ball will pass when the sun is on the equator; l, the latitude or declination lines, and m the hour-lines.

As shown in Fig. 4, a modified arrangement may be madeby which the equation of time may be set off on the instrument so that it will show mean solar time. The semicircular ring a is fastened to a bottom, j, which forms a half-circle and moves around a screw, 12, which passes through its center and into the centerof another bottom, r, also, a half-circle, and a little larger than bottom j. The chains 6 are fastened to bottom a", and at the back a standard, 8, isfastened to bottom r, to which standard the chain that carries the adjustingscrew f is fastened, by which arrangement bottom r can be suspended parallel to the plane of the equator, and bottom 3', with semicircular ring a, move freely, also parallel to the plane of the equator, over bottom r, around the center 19, and have avernier, t, connecting the two bottoms, and upon which the equation of time can be set off.

To find the latitude of the place, level the dial about fifteen minutes before the sun comes on the meridian and bring-the shadow of the ball on the line of declination for noon of that day. As long as the shadow of the ball goes down the sun is rising, and the shadow must be kept on the line of declination by motion of the latitude-arc d, where the hour-line of 12 crosses the declination-line. \Vhen the shadow is at a standstill on the declination-line, it is noon,

and the latitude may be read oif on the latitude-arc d, and the dial is regulated for that 5 latitude.

If the shadow of the ball is kept on the declination-line it will show the time when it crosses the hour-line.

The standards 0, to which the ring a is sus- IO pended, can be used as sight-vanes, and will give a true east-and-west line.

The declination-lines, and also the hourlines, which may be subdivided in proportion to the size of the instrument, may be in several I 5 different colors, so as to readily catch the eye.

The instrument may be made of any suitable material.

Cards with the suns declination and equation of time should go with each instrument,

20 and abridged tables of the same may be printed or fastened 011 any convenient part of the instrument. The bottom j is also used to keep the semicircular ring in shape.

I do not limit myself to the particular eon 25 struction herein described, as it is obvious that many diiferent instruments, all carrying out the same general idea, could be made.

I am aware that it is not new to combine a rocking semi-circle, a revolving solar plate pivoted inatop plate and having a small hole 0 for the passage of the sunlight, and two levels at right angles to each other; but

What I do claim as new and of my invention, is

1. The semicircular ring a, marked with 3 5 lines 7c lm, arranged on pivots b, and provided with an adjustable are, d, in combination with the frame 6, mounted on a bottom, j, attached to the ring, said frame being adapted to be moved up and down, as shown and described. 0

2. The combination, with the ring a, of the semicircular bottom j, movable about a screw,

1), a larger semicircle, 1", parallel to the equatorial line It, and the vernier t, connecting said semi-circles, as shown and described.

NIELS LA'RSEN.

\Vitncsses:

WM. STUEFER, R. F. S'rnvnNsoN.