65.—A Plunge Battery adapted to a Set of Elements, as shown in Figure 63. They may be lifted out and placed on the "Arms" to drain. Fig. 66.—An Edison-Lalande Cell. .................................. Fig. 67.—A Tomato-Can Cell; Sectional View. ....................... Fig. 68.—The Tomato-Can Cell Complete. ............................ Fig. 69.—Two Methods of Connecting Cells so as to obtain Different Voltage and Amperage Values. ...................................... Fig. 70.—Small Storage Cells. ..................................... Fig. 71.—How to make the Plates for a Storage Cell. ............... Fig. 72.—The Wood Separator. ...................................... Fig. 73.—The Complete Element for a Storage Cell. ................. Fig. 74.—A Battery of Home-Made Storage Cells. .................... Fig. 75.—Gravity Cells. These consist of zinc and copper elements, immersed in a zinc-copper sulphate solution. They cannot be easily made, and are best purchased. The illustration also shows the star-shaped copper and "crowfoot" zinc element used in a gravity cell. ............................................................. Fig. 76.—A Current of Electricity flowing through a Wire will deflect a Compass Needle. ......................................... Fig. 77.—If a Loop of Wire is formed about a Compass Needle, the Deflection will be greater. ....................................... Fig. 78.—Iron Filings clustered on a Wire carrying a Current of Electricity. ...................................................... Fig. 79.—Magnetic Phantom formed about a Wire carrying a Current of Electricity. ...................................................... Fig. 80.—Magnetic Phantom formed about several Turns of wire. ..... Fig. 81.—Paper Tube wrapped with Wire for Experimental Purposes. .. Fig. 82.—Showing how the Lines of Force "Leak" at the sides of the coil, from a Coil of Wire, and how they are concentrated by an Iron Core. ............................................................. Fig. 83.—The Principle of an Electro-Magnet. ...................... Fig. 84.—if you wrap some insulated Wire around an Ordinary Nail and connect it to a Battery, it will become an Electro-Magnet. ........ Fig. 85.—If you wind the Wire around a small Paper Tube into which a Nail will slide easily, the Coil will draw the Nail in when the Current is turned on. ............................................. _By permission, from "Solenoids" by C. R. Underhill._ Lifting-Magnets of the type known as Plate, Billet, and Ingot Magnets. .......................................................... Fig. 86.—Showing how a Current of Electricity may be induced by a Bar Magnet and a Coil. ............................................ Fig. 87.—A Horseshoe Magnet and a Coil arranged to produce Electric Currents by _Induction_.