US100691A - Improvement in sun-dials - Google Patents

Description

L. I. TRUEG.

Sun'Dial. No. 100,691. Patented March 8,.18'70.

To all 1071,0111, itmcty concern:

[UNITED STATES PATENT OFFICE.

L. IGNATIUS more, or sr. VINGENTS, PENNSYLVANIA.

5 IM PROVEM ENT IN' SUN-BDIALS.

Specification forming part of Letters Patent No. 100,69]; dated March 8, 1870.

Be it knownthat I, L. IGNATIUS TRUEG, of

St. Vincents, in the county of 'Westmoreland and State of Pennsylvania, have invented certain new and useful Improvementsin Hcli-' orama; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the ,accompa nying drawings, and to the letters of reference marked thereon, making a part of this speciiication. i l i l l The nature of my. invention consists in the construction and arrangement of an instrument by which the degrees'of latitude and the sunltin'ie and clock time is measured, and which instrument I call the heliorama.

p In order to enable others skilled in the art to which my invention appertains to make and use the same, I will now proceed to describe its construction and operation, referring to the View of the plate whose shadowmeasures the sun time. l i v My instrumentthe helioramais composed of two instrumentsthe helioclisis, tomeasure the. declination of the sun from the equator, and consequently the degrees of latitude; and the hemerophora, by which the shadow of the sun time is measured.

A represents the b2LSBI116IliJ-2lu plate of wood 1 orany other suitable material, having a recess in its upper side for the insertion of, a compass wherewith the instrument is adjusted.

l The needle of the compass has to coincide with y the line N S on the bed A, so that the north pole of it shows toward N, thus bringing the:

sides, of the bed due north and south and the,

ends east and west. It is self-evident that the basement or bed A has to be put level when the instrument is set up "for use. a

At each end of the bed A is placed a side piece, B, perpendicular with the bed. The lower parts of these side pieces have nearly the width of'the bed or basement. The higher are narrower, having a hole wherein the pins or axles c a'of the middle piece, 0, are revolving. i

On the outside of the side pieces, B B, are

arcs L L, with degrees marked thereon, one

for the latitude and the other for the height of the celestial equator, the arms a a being each provided with a finger, b, for indicating the same. A V

G is the middle piece or plate, revolving upon the pins a a in the side pieces,- BB. Cross wise ou the plate 0 is placed a graduated are,

D, called the cliseologet. It is graduated so that degree 0 is in the middle, and from this degrees are counted on both sides up to 25. Strictly required, however, are only 23%, because the declination of the sun on the solstices does not exceed said number of degrees.

E is the equatorial gnomon, formed of a semicircular brass plate of the same radius as the arcof the cliseologet D. The gnomon E is provided with two feet, which are inserted in the plate G. The two arcs D and E biseet each other at right angles, so that a radius perpendicular with the diameter or base of the gnomon E will stand perpendicular with the are or cliseologet D at degree 0, and its lower end, being the center of the semicircular gnoniomwill touch that are on which th degrees are marked V When the instrument is set up for use, the i plate must be put level, and the compass has to shownorth and south, as indicated by the letters N From this it appears that the gnomon E, or rather its diameter or base,isin the direction east and west, and since it follows the equator is called the equatorial gnomon. It must be remarked that the .de grees of latitudeon the western side piece, B,

are laid out thus, that the are L, on which the degrees are measured, has its center in the center of the pin a; and, further, in the distribution of thedegrees one-half degree (thirtythree minutes) must be lost, so that on the place where 89 27 should come 90 will be marked. The. reason for this will appear hereinafter. For convenience sake, the surface of the middle pie(e or plate, 0, bears a list of the dates of the year, with thedegrees of the de clination of the sun marked opposite the re spective dates. In case the degree of latitude the indicator 1) shows the degree on the are L of the western end piece, B. The arc L on the opposite end piece is grac'luated in prethe same manner, except that the degrees run cisely in the opposite direction, so that when the indicator shows on the latitude side the indicator on the celestial-equator side will show 90. The sum of the latitude and the height of the celestial equator is always equal to ninety degrees. The shade of the sun cast by the gnomon LE on the cliscologet D indicates the declination of the sun from the equator, north or south. During the season when the sun is actually south of the equator the shade falls north of degree 0 on the cliseologet; but during the season on which the sun is north of the equator the shade falls south; but in case the degrees of latitude of the respective places are not known, then the list on the plate 0 has to be consulted. Suppose we have the th of February. The list shows that on this date the declination of the sun amounts 14.4". Having adjusted the instrument with regard to north and south, &c.', Ithen turn the middle pieee,-C, untilthcshadow of the sun is cast on the said degree north of dcgree 0. After this I look 011 the are L. IVha-t degree is indicated thereon by the indicator? The very same is the degree of latitude of the place.

The advantages of this part of my inven tion are that the helioelisis shows the declination of the sun on the different seasons, and it does this not only on the mid-day hour, but

on every h0urforenoon and afternoon. Its

greatest advantage, though only a consequence of the first, is this, that it shows the degrees of latitude in case they are not known. The helioelisis will, for this reason, be of great service to mariners. \Vhen used on the 'sea, it has to be kept in its direction (north and south) by means of a great magnet. It might be asked how the effect of the refraction oi the sunbeams in our atmosphere is corrected. By the simple means that on the distribution of the degrees on the are L thirty-three minutes arelost, as described above. The refraction of the sun is, at 10, 10"; at 21; at 33", and increasing until at it is 33. Another point remains to be corrected, if deemed necessary. The sun, when casting a shadow, does so not from its center, but from the outline of its disk. In order, w, to get the shadow, as it were, cast from the center, the radius of the sun-disk, which is sixteen minutes, must be added to the degrees of latitude, which can be effected by subtracting them in the gradature of the are L. So that, with this second correction, 90 will be marked where 90(16+33)-that is, 89 and.1lought to be.

On the rear side (north side) of the middle piece, 0, the hemerophora is attached. This consists of a bearer, G, secured to the side of the plate 0, said bearer being provided with a semicircular cut, as shown in Fig. 2. On

the inner side of this cut is a groove all around the are, which admits an are, H, called the horologet. This are is made of brass or other suitable material, and bears upon it the description of the hours of the day, and is for this reason called horologet. The bearer might also properly be called equator, for the reason that it has to be set, by means of the revolving middle piece, O. in accordance with the celestial equator, it being exactly perpendicular, or at right angles with the middle piece, 0. The division of the are H regarding the inscription of the hours is simplythis: 6 oclock of the morning and 6 o clock of the evening are distant from each other, so that a straight line drawn from 6 to 6 passes through the center of the arc. The remaining hours are 15 distant from each other. Thus if we call 6 oelock of the morning degree 0, 7 ocloek comes on degree 15. 8 on 30, &c., 12 oclock on degree 90. The horologet is more than a semicircle, in order to gain space for the inscription of at least one hour more for the morning and one for the evening. Thus provision is made for the summer season, when the day is longer than twelve hours. The horologet H can be shifted around its own center. The motion is, however, very small, amount ing in all only to the space which half an hour,

or, more accurately, thirty-one minutes, on the horologet occupy. The end of this motion is to set. the horologet so that it indicates the middle time, or the time of a correct clock, for the sun time differs more or less from the latter, itbeing sometimes too slow, sometimes too fast.

I represents the meridional gnomon or in dicator, consisting of a'brass plate, (see Fig. 5,) the upper end, (I c (I, being an arc, the center of which is i. As it is represented in the drawings, the arc extends on both sides of e a little over thirty degrees. Of strict necessity they are, however, only twenty-three and onehalf degrees on both sides, these being the amount of the declination of the sun; but it seems preferable to let the are ext-end farther, for the sake of obtaining a full and distinct shade cast on the horologet, especially at the time of the solstices. The radius c has to be obtained thus: Take the radius of the horologet, .add to it one thirty-second part of its own length. I. The reason for this will be hereinafter set forth. The gnomon has to be set thus: The lined c has to stand perpendicular 011 the horologet, passing through its center. The line f f bisects the horologet at right angles, and,

moreover, touches-the surface of the inner side of the horologet, so that the pointi touches the middle of it, or, more accurately, z touches that circular line passing along the middle of the horologet, on which the divisions of the hours are marked.

It may here be observed that the shape of the bearer or equator G is not essential, only so that in all cases it is perpendicular to and The sum is the radius of the gnomon.

revolves with the middle piece, 0; that it bears around in this revolution the horologet H, giving to it the direction described above; that it admits the horologet to be shifted around its own center, and that it carries along, when turned around together with the horologet, .also the gnomon I and the appara tus required for shifting the horologet. This apparatus will be hereinafter described.

The advantages of thehemerOphOra are that it shows at everyseason of the year, at

every time of the day, at every place on the globe the correct time-that is,the time which a correct clock shows. It might be'asked whether the refraction of thesunbeams'in our atmosphere would not affect the hemerophora, preventing it from showing the correct time. It does not, since provision is made for that.

The gnomon Iis, as described above, shaped so that the'radius'of the'arc d 6 dis by one thirty-second greater than the radius of the horologet.

The effect of this is that on the morning the shadow is cast backward, on the evening forward. If, for instance, 011 the 21st of March the run rises in fact, not in'appearano e, at 6 o clock, (sun time,) the shadow of the rising sun is cast backward by a few minutes, showing 5.53. As the apparent sun, so

to speak, rises over the horizon, little by little the shadow falls on 6 -o clock at the very point of timewhen the real sun rises. Under the bearer G is a box, J, of semicircular shape, having upon the inside of its rim and on its bottom the days in the year, so arranged that the days, when there is; no variation" between the sun and clock-time, will beimlnediately below the center of the gnomon I, and the names -or dates will come in regular rotation. on each side of the center--- that is, one sidefor the sun time becoming slower and the other side 'for'it becoming faster, only such dates,*however, being put in where the difference is not less than one min ute from the preceding date. I

In the bearer G is hung a finger, m, pointing toward the names in the box J. This finger is, by suitable mechanical devices, con- 1 nected with the horologet H in such a manner that, moving it (the finger) one space, the I horologet will be turned around its own center the distance of one minute. By this means I am enabled at anytime so reset the horologet that it will show the exact time;

Having thus fully described my invention, Y what Lclaim as new, and desire to secure by Letters Patent, is p 1. Theequatorial gnomon E, in combination with the eliseologet D and revolving 4. The combination of the bed A, end pieces,

B B, plate 0, pins (1 a, fingers b b, arcs L L, cliseologetD, gnomon E, bearer G, horologet H, and gnomon I, all constructed and arranged as described, substantially as and for the purposes herein set forth.

In testimony that I claimthe foregoing I have hereunto set my hand this 1st day of February, 1870. a a

L. IGNATIUS TRUEG.

Vitnesses:

J. M. STooPs, C. L. EVERT.

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