The art of decorating dry goods windows and interiors

by L. Frank Baum

A STUDY IN ASTRONOMY.

One of the most remarkable mechanical displays yet conceived is that designed by M. M. Mohnkern, called “A Study in Astronomy.” It is not theoretical, but has been made and exhibited by Mr. Mohnkern and has attracted and delighted thousands. It is, to be sure, rather complicated in construction, and requires a mechanic to build it, so that it will work smoothly; but it is thoroughly practical, and so very novel and beautiful when completed that it will repay the labor expended to produce it.

The device is intended as a background for any display of goods, and may be utilized by any merchant who has a show window, the expense being very little aside from labor.

In his description Mr. Mohnkern says: “In looking at this display through the show window one can easily imagine he has been transferred to some other planet and is looking at the solar system, where old mother earth revolves slowly around the sun. In the distance the moon is changing, first in the dark of the moon to the first quarter, then to the half, the third quarter and the full moon, decreasing again in the same way. The stars twinkle as naturally as they do in the heavens; the whole display is grand and awe inspiring.” We can well believe this.

Fig. 1 is the front view of the window, showing the sun, moon, earth and stars, and the orbit of the earth where it revolves around the sun. A strip of lumber was bent into a large circle, almost the full size of the window. Black cambric was stretched from this to the four sides of the window, and openings cut in the corners for the stars and moon, as represented, C C C being the stars, and D the moon. Back of each of the three stars in each corner small wheels were placed (see F F F, Fig. 2). These wheels were twice as large as the stars, and placed so that the center of each wheel was directly opposite a point of a star. Then half of each wheel was covered with black cambric and the other half with bright red. As the wheels revolved very fast, it made them twinkle like real stars. The moon was a large round hole cut in the cambric with yellow tissue paper pasted back of it, and an electric light suspended behind the opening. A disk is made, a little larger than the opening, as shown in Figs. 5 and 6. A, Fig. 5, is the opening of the cambric; B is the disk; C is where the disk is connected with the axle. This disk is covered with black cambric and placed between the cambric background and the window pane. Thus it will be seen that as the disk slowly swung around, the changes of the moon would occur.

Two more strips of lumber were now bent into circles, about eighteen to twenty inches smaller in diameter than the first circle. One of these was placed flush with the first circle and held in position by means of braces I I. This circle was then covered by stretching black cambric snugly over it, and an opening was cut in the center to represent the sun (B, Fig. 1). Yellow tissue paper was pasted over this, and an electric light suspended directly back of it.

Star-shaped openings were now cut in this cambric, as shown by the stars in the central portion of Fig. 1.

The second circle was placed about six inches back of this (see Fig. 3, A 1 and A 2). It was held in position by braces F F, Fig. 3. These two circles formed a track on which the earth slowly revolved. Another circle was next formed, similar to the first one, except that this had four spokes, I I I and J, Fig. 2. The spoke marked J was long enough to reach the center of the globe and connect to an axle, as seen in Fig. 3. This circle was also covered with black cambric, and irregular holes cut in it (H H H, Fig. 2), over which pieces of red tissue paper were pasted. These are represented by the irregular patches in Fig. 2. This rear disk was fastened to a pivot (Fig. 3) and placed three inches back of the front disk in which the stars and sun were cut. As it slowly revolved it carried the globe around with it, and the irregular tissue paper opening coming opposite each star caused the stars to twinkle like those in the corners.

The earth was constructed as follows: Two bushel baskets were procured, the handles cut off, and a brace nailed across the center of each. Holes were bored in the middle of these braces, and an axle inserted (B, Fig. 4) and made fast to the bottom of the basket. Then the spoke J, Fig. 4, which has a hole in the end, is slipped over the axle and the other basket placed in position and fastened opposite the first. The baskets were left far enough apart to allow them to revolve. In Fig. 4, A A, are the baskets, B is the axle, c c c c braces, J the spoke, corresponding with J in Figs. 2 and 3.

The profile drawing in Fig. 3 will enable you to see the mechanism at a glance. A1 and A2 are the circles on which the globe representing the earth revolves; B is the disk with the long spoke, J, placed between these two circles; C is the pivot which causes disk B to revolve. D D are the braces holding disk B in position. F F and I I are the braces holding A1 and A2 in position; G is the pulley on pivot C that run the different parts; K is the main belt leading from the basement; L L L are belts running to pivots H H H. All framework liable to show should be made black; also have the cords you use for belts black.