Page:Popular Science Monthly Volume 89.djvu/627

 Popular Science Monthly

��613

��To Make a Dry Battery Having Lasting Qualities

FOR the person who cares to experi- ment, this type of a battery is a good example to try out; for, if properly constructed, it will last much longer than the ordinary dry cell. The container consists of a glass jar of a size suitable for the battery. Coil up a cylinder of heavy zinc plate to fit closely against the inner surfaces of the jar and line the

inside of the zinc

, -.CARBON /

��ZINC CYLINDER (

�� ��with a good grade of thick blotting paper. A paste is made as follows: For the liquid mix together 3 parts water to one part muri- atic acid. (In mixing acids and water remember to add the acid to the water slowly while stir- ring the water.) The body matter for the paste is made of four parts powdered charcoal, 2 parts flour and i part plaster of Paris. These parts are measured by volume. Mix this powder with the acid liquid to form a paste.

Procure a carbon from a discarded cell and place it in the center of the jar, then fill in around with the plaster to the top of the jar and finish by sealing with wax. After this stands for a few hours it will be ready for use.

��A Home-made dry battery cell

��Insulating the Ground Connection in Radio Work

A GOOD ground connection is of the utmost importance in radio work- ing. If you use the gas, steam or water pipes be sure that they run out to the system of mains with good electrical conductivity. In some parts of the country it is customary to insulate gas or water pipes at the meters. Where this occurs a wire shunt should be connected between the house-pipes and the outside mains.

��A Weight and Pulley to Adjust Flexible Lamp Cords

WHEN working around a machine it is necessary to have a portable light. A good way to make one is as follows: An elec- tric lamp is let down from the ceiling to the floor. This wire is run through a pulley placed in the ceil- ing as at ^. A weight B oi ]/^ ^ pound is placed on the wire be- " tween the pulley and the out- let. A piece of tape is then wrapped on the wire on the outside of and below the pulley at C to keep the lamp from going up out of reach. When the lamp is to be used under the machine, take hold of the wire above the light D and pull it down. Afterwards the weight A pulls the lamp up into its former place again.

���To Lengthen a Shot- Chain on a Pull -Socket

THIS simple operation will prove to be an economy to those handling these goods. It will be found that the small balls are split. These are opened up with a knife-blade until the edge of a cold chisel will take effect. They are then further opened up to release the small pin on the inside. This pin has a head at each end. One ball must be removed so that an extra pin may be had to start the lengthening of the parts. The pins are then put in to form a part

���The small balls are split and may be opened up with a knife-blade and a chisel

of the chain instead of being just a fastening means. To do this properly the parts are laid out on a bench, and the balls clamped over the ends of the pins with pliers. — E. B. Willi.\ms.

�� �