NO doubt some of those who read this article saw at the St. Louis Fair the wonderful electric writing telegraph, or "Telautograph," as it is called.

Here a man sat at a desk with a pencil and wrote and drew pictures, while above him, on another piece of paper in a separate machine, a pencil guided itself in the same manner and drew the same lines. It was very interesting, especially when one thought of writing from one city to another, as can be done with this machine.

Having seen the instrument at the Fair, as a boy, I set to work to devise one for myself when I returned home. At first I had trouble, but finally I hit upon the simple scheme of the apparatus shown in the drawings. This is really surprisingly easy to make. The principle is very simple also.

You see, in the first place, the pencil P is held in a wooden arm or lever A, and this wooden arm is pivoted on a screw eye S at about the middle. At the outer end of this arm or lever a string I fastens and runs to the other end of the line to a similar lever, while rubber bands R at either end keep this string tight. You can see from this how, if you swing the pencil sideways so as to move this lever about its pivot S, that the pencil at the other end will slide sideways back and forth in exactly the same way as you move this first pencil. This string I therefore carries all the side motions of the pencil.

The pivot S, however, fastens to the end of a bell crank B, made of wood and having arms at right angles of equal length pivoting on a screw D at the corner of the bell crank. From the outer arm of this bell crank-which, by the way, lies parallel with the first lever arm holding the pencil - runs a string M to a similar bell crank on the instrument at the other end of the line.

Now if you move the pencil up and down, this moves the second arm of the bell crank right and left, and pulls or pushes the string M. Rubber bands R keep this tight as before, so that any up-and-down motion of the pencil P through the moving of this bell crank transmits up-and-down motion to the pencil at the other end of the line, and any up-and-down motion at one end carries exactly the same at the other end. We therefore have an instrument which produces two motions: right and left carried by the string Z,, and up-and-down carried by the string M, so that between the two strings any combination of writing motions - up and down, horizontal, circular, or slanting - are transmitted and written at the other end of the line. This makes a wonderful writing telegraph, and one from which you can get a great deal of amusement. This toy is very simple to make. The base is nothing but a piece of inch wood, about eight by ten inches or even larger. The first lever A is made of half-inch wood. Near one end a hole is bored the size of the lead pencil you are going to use, and a saw cut is made down through the hole and extending a little distance back, as in Figure 2. A small hole is drilled through one side just back of the pencil and extending as far as the saw cut. By screwing a screw eye through this hole to the wood on the opposite side, the pencil is clamped tightly on the end of the lever and can be held at any height from the paper. A small wood screw farther back at the end of the saw cut will prevent the wood from splitting. Back of this the lever may be cut down so that it is not over a half an inch square.

The bell crank is made of thin cigar-box wood with each arm half as long as the first lever A. In other words the distance from the screw eye S at the center of the lever A to the screw D at the corner of the bell crank is equal to the distance from S to the pencil P on the other lever. In mounting the levers and bell crank, be sure the bearings work freely with little friction; under the bell crank B - and between it and the baseboard - a washer is fitted around the screw D to keep the bell crank from rubbing on the board.

The strings which form the line are ordinary hemp shoe thread and can be fastened to holes in the levers or to screw eyes, - the latter making a neater looking job. It is very easy to see how the rubber bands are fastened to keep the strings of the line always tight. The instrument should be adjusted so that when it is at rest the arms and bell crank are in the positions you see.

The writing pad is nothing but a little penny tablet that you can tack on the board, and a small pencil can be put in the proper location so that the pencil can reach all parts of the board.

In connecting the instruments, run a string from the straight lever to the same location on the other instrument, while the bell cranks are connected by a separate string M. If the instruments are identical, with the bell cranks on the same side, thev will write exactlv alike: but if they are on opposite sides, - as shown in my sketch here, - then the one instrument will write upside down.

If you want the line to turn a corner, you can run the string through screw eyes or a little block of wood screwed into the wall, as shown in Figure j. If you want to run the line upwards, you can run the strings through the screw eyes as shown in Figure 2, having a similar connection at the top end of the line, which may carry the strings in through the window to the table on which the other instrument is set.

The rest of the toy is so simple that it needs no further instruction than the drawings.