The whole motor is fastened with screws to a wood base, 8 in. long, 6 in. wide and 1 in. thick.  Two terminals are fastened at one side on the base and a switch at the other side.

To connect the wires, after the motor is on the stand, the two ends of the wire, shown at B, Fig. 1, are soldered together.  Run one end of the field wire, shown at A, through a small hole in the base and make a groove on the under side so that the wire end can be connected to one of the terminals The other end of the field wire C is connected to the brass screw in the brass brush stud.  Connect a wire from the other brush stud, run it through a small hole in the base and cut a groove for it on the under side so that it can be connected through the switch and the other terminal.  This winding is for a series motor.  The source of current is connected to the terminals.  The motor can be run on a 110-volt direct current, but a resistance must be placed in series with it.

** Protecting Tinware [347]

New tinware rubbed over with fresh lard and heated will never rust.

** Another Optical Illusion [348]

After taking a look at the accompanying illustration you will be positive that the cords shown run in a spiral toward the center, yet it shows a series of

[Illustration:  The Cord Is Not a Spiral]

perfect circles of cords placed one inside the other.  You can test this for yourself in a moment with a pair of compasses, or, still more simply, by laying a point of a pencil on any part of the cord and following it round.  Instead of approaching or receding from the center in a continuous line, as in the case of a spiral, you will find the pencil returning to the point from which it started.

** Substitute for Insulating Cleats [348]

In wiring up door bells, alarms and telephones as well as experimental

[Illustration:  Insulators]

work the use of common felt gun wads make a very good cleat for the wires.  They are used in the manner illustrated in the accompanying sketch.  The insulated wire is placed between two wads and fastened with two nails or screws.  If one wad on the back is not thick enough to keep the wire away from the support, put on two wads behind and one in front of the wire and fasten in the same manner as described.

** Electrically Operated Indicator for a Wind Vane [348]

The accompanying photograph shows a wind vane connected with electric wires to an instrument at considerable distance which indicates by means of a magnetic needle the direction of the wind.  The bearings of the vane consist of the head of a wornout bicycle.  A 1/2-in. iron pipe extends from the vane and is held in place by the clamp originally used to secure the handle bar of the bicycle.  In place of the forks is attached an eight-cylinder gas engine timer which is slightly altered in such a manner that the brush is at all times in contact, and when pointing between