Two uprights B are now made, 2 3/8" long, 5/8" wide and 1/4" thick, with the lower ends cut to form shoulders, as shown in Fig. 4. A cross-piece R, 1/4" thick and 5/8" wide, is nailed to the tops of supports. The lever C is 3 5/8' long, 3/8" wide, and 3/8" thick.

The armature F consists of a flat piece of soft iron 2" long, 1/2" wide and 1/8' thick, with a hole drilled through the center for the screw M, which fastens to the lever C. The screw-eye N is 5/8" from the end of C, a hole first being made with an awl, to prevent the splitting of C. Another hole is also made with an awl 1" from the other end of C to receive the wire nail or piece of steel wire which serves as a bearing. The holes in C should be tight; the corresponding holes in the supports B should be large enough to allow free play of the lever C and prevent binding, and yet be without side motion.

At the front end of the lever C make a hole to receive the small wire nail or large pin L, which should move freely, so as to turn with the spring T when adjusting the tension. The end of L is turned into a hook to hold the loop of the spring. The screw-eye K holds the outer loop of the spring, which should be without tension when K is almost unscrewed. The spring should be quite sensitive, as the lever C requires to be kept nicely balanced, and respond easily to the "pull" of the electro-magnet on the armature. A rubber band may be used in place of the spring, but is not so good for the purpose. On the other end of the lever C tack a strip 3/8" wide of thin tin: a piece of an old tintype will do nicely. This is to increase the sound of the "click." A similar strip is tacked around P for the same purpose.

The frame for regulating the movement of the lever C consists of the upright posts Q and R and the cross-pieces P and S, made from §" square strips screwed, together, as shown in Fig. 4. The lower end of the uprights Q and R have shoulders, and are glued to prevent loosening. Care should be taken to make the holes for the screws with a sharp awl, so as not to split the wood. The wooden parts being all in position, excepting the lever C, the electro-magnet is attached to the base by a screw, the inside ends of the coil wire being left free to attach, one to the line wire and one to the wire from key. In the regular telegraph instrument these wires are carried through holes in the base to terminal posts and key; but these are omitted in this description, but may be added if desired.

Fig. 4

The lever C is now fastened in place by the wire nail T and the spring J attached. When the lever is in correct position the armature should, by pressing it lightly with the finger, not quite touch the ends of the cores, which are known as the poles of the magnet. The movement of the armature should be less than 1/8", and is adjusted by the screw-eyes N and O.

The Battery.

The battery is of the form known as the " Gravity " type, and consists of a jar of glass or stoneware ; the positive element, zinc; the negative element, copper, and an exciting solution of sulphate of copper commonly called " blue vitriol." A battery can be purchased at low cost, and but little instruction is to be gained by making one ; but the method is given for those who desire to try it. From sheet zinc cut three strips 2" wide and 6" long. Bind them together in the center with two complete turns of another strip 1/2" wide and long enough to leave a free end 8" long. Separate the ends so they will form a six-pointed star. From some sheet copper cut three strips 2" wide and 6" long. Rivet together in the center with copper rivet. Punch another hole through the strips just above the rivet and fasten a piece of copper wire, which, except where it is fastened to the strips, is covered with rubber insulating material. The ends of the strips are then bent apart to form a star similar to the zinc. The copper is then placed in the bottom of the jar, which should be of about 8 quarts capacity. A pound of sulphate of copper in crystals is then placed around the copper strips, and water added to fill the jar to within about an inch of the top. A strip of wood is then placed across the top of the jar, the zinc lowered into the water till the top of the strips are covered about a half inch; the binding strip is then carried around the piece of wood, to hold it in position. Several hours are required for the battery to generate its full current of electricity. The line wires are attached, one to the zinc strip and the other to the copper wire, the insulation on the latter being removed and the line wire twisted enough to give plenty of contact. A battery of one cell makes only a weak current; so all connections must have plenty of surface to enable as much of the current to flow as possible. As brass corrodes, all connections should be brightened with a file or emery-cloth; and soldered if permanent. The brass terminal screws will need polishing at times, to enable the current to flow easily. It is to obviate this difficulty that platinum points are used on regular instruments.

Very few people have heard of automobile banks. Such, however, is the case, and the new institution is the property of the town of Mezieres, in the Ardennes, France. In order to reach a savings bank the peasantry there have been compelled to leave their work and come to town, which meant to many a journey of several miles. Now, instead of having to go to the bank to deposit their savings, the residents on the outskirts of Mezieres will have the bank brought to them. The new vehicle is unique in construction. It is propelled by electricity, and has four seats, one in front for the driver and three in the rear for the staff of the institution. These three seats surround a revolving table, located in the center of the carriage, on which the business of the bank may be transacted. Writing-desks capable of being folded up when not in use are arranged over each of the seats in such a way that when open they extend out from the sides of the carriage in a manner suitable for the use of persons standing outside who desire to open an account with the bank. On the table are to be found shelves for books, adequate stationery for the use of the clerks, and a small metallic strong-box. On certain prearranged days the car makes a tour of the country districts, stopping here and there as long as it may be necessary to dispose of the business in hand.