A storage cell made of lead plates in the manner just described would not possess sufficient capacity to make it worth while as a practical cell. It has been found that if instead of a solid flat plate, a framework or grid is used, consisting of a set of bars crossing one another at right angles, leaving spaces between, which are filled with a paste made of lead oxides, there will be a considerable gain in the capacity of the cell. A Homemade Storage Cell. The storage cell illustrated in the accompanying illustrations is very simple to make and a battery of them capable of delivering six or eight volts will prove a very convenient source of current for performing all sorts of electrical experiments. [Illustration: FIG. 39.—Showing how the Plates for a Storage Cell may be made from Sheet Lead by boring it full of holes and filling with paste.] The plates are cut from sheet lead from one-quarter to five-sixteenths of an inch thick. The height and width will depend upon the size of the jars used. There are several sizes of rectangular glass storage cell jars on the market, and if the plates are made about three inches wide and three and one-half inches high, they will fit the smallest size of jar. A lug about one inch and one-half long and three-quarters of an inch wide is left projecting at the top. Three plates are used in each cell. Each cell will have an E. M. F. of two volts when fully charged. In order therefore to have a battery capable of delivering six volts, three cells will be necessary. Nine plates will be required for three cells. The body of the plates should then be drilled full of holes about one-eighth of an inch in diameter as shown by B in Figure 39. The plates are now ready for pasting. Select three of the plates and mark them with a small cross. These are to be *positive* plates when finished. The paste for these plates is made by mixing red lead with diluted sulphuric acid. The paste should form a good stiff mixture. Lay the three plates upon a smooth board and press the paste carefully into the holes with a flat stick. They are then laid aside to dry and harden. [Illustration: FIG. 40.—A set of three Plates composed of One Positive and Three Negatives assembled to form a Cell.] The six remaining plates are to be *negatives* when finished and they are pasted in identically the same manner as the positives except that the paste is made of a mixture of yellow lead and dilute sulphuric acid instead of red lead. A pasted plate is shown at the right in Figure 39. Cut six rectangular pieces, three by three and one-half inches, of heavy blotting paper or thin whitewood. The thin wood used in the construction of fruit baskets may be used for this purpose. These rectangles are to be used as "separators" between the plates. [Illustration: FIG. 41.—Glass and Rubber Storage Cell Jars which are on the market for the Electrical Experimenter and may be purchased very reasonably.]