Faure's Secondary Battery.—Camille A. Faure, a French chemist, constructed a cell based on Plantes about 1880. But he substituted mechanically prepared plates for those prepared by electricity, by coating their surfaces with a paste of red lead (minium, Pb0,) and sul phuric acid, which, when subjected to electrical action, was rapidly reduced to peroxide on the one plate and spongy lead on the other. After this was applied it was coated with paper. and each plate then enveloped in felt to retain the coating on the surface and to insulate the plates from each other. They were then rolled together and placed in the acid ulated water in the cell, and subjected to electric action with reversals, and in a few days the cell was ready for use, The great advantage of the Faure over the Plante cell consists in the rapid reduction of the minium instead of the slow reduction of the metallic lead.
It soon developed serious faults, however ; but the rapid preparation of the plates was co great an advance that various inven tors worked patiently to overcome the faults which had developed. The various improvements of Swan, Sellon, Vo mar, Shaw. and others resulted in pro ducing the improved cell shown in Fig. 2.
This is made of different sizes and a variable number of plates, according to the purpose for which it is intended. The standard type shown, made by the Accumulator Co., of New York, called the 15i cell, has 15 plates, 7 positives and 8 negatives, those plates being called positive which are connected with the positive pole in charging, and from which the external current flows in dis charging ; the others being known as negative. Each positive plate is 9'it in. high, 8,1 in. wide, and 1 in. thick ; and each negative, 93 in. high, 91 in. wide, ands in. thick. They are of lead cast in the form of grids, with square open ings to hold the paste, as shown at A, Fig. 3, this form being the invention of Swan.
Each opening is I in. square at the surfaces, but smaller in the center, the walls being thicker, sloping inward from each surface as shown in cross section at B, Fig. 4, an improvement by Sellon to pre vent the paste from falling out. These openings are filled with the paste of lead oxide and sulphuric acid ; minium, being used for the positive plates, and litharge, MO, for the negatives. From one of the upper corners of each plate a lead bar extends as shown in Fig. 3.
It is in. wide, the same thickness as the plate, and extends 2i in. above the highest plates.
These vertical bars on each set of plates are attached to a hori zontal bar of the same width, as shown in Fig, 2, connecting the set of plates together and keeping them a given distance apart, the space between each two positives beings of an in. and that
between each two negatives a in., each set with its bars being a single casting. The horizontal bars are extended and the ends turned in for convenience, forming lugs for connecting the cells into a battery (see Fig. 2). When the plates are ready to be set up, the 7 positives are passed in between the 8 negatives, so that they alternate, each positive being between two negatives with a in. space between them. In Fig. 2, the positives are shown with their bars to the right and the negatives with their bars to the left. As the outside plates are negatives and the outside surfaces inactive, the same number of active sur faces, positive and negative, 14 in each set, are adjacent to each other within. In each negative plate a number of openings are left without paste, into which are drawn plugs of soft rubber, which project in. on each side, resting against the positives and holding, the plates that distance apart. Two plates of glass of the same size as the lead plates are placed outside, one on each side, against the projecting rubber plugs, to keep them from being pressed out. and all the plates are bound together and held in position by strong • rubber bands. They are then placed in a glass jar 11 in. long, 81 in. wide, and 13 in. high outside, and rest on two strips of wood placed in the bottom to allow free circulation of the • fluid The average E.M.F. of this cell is about 2 volts, its internal resistance .005 ohm, and its capacity 350 ampere hours, its best working rate being 35 amperes for 10 hours. The cell weighs 125 lbs., which can be reduced by using h in. and in. plates, but it is not so ble. The Julien Accumulator is the invention of Edmond Julien, of Belgium. Its general principles are essentially the same as have been already described, but his specific claim is that the grids are made of a special alloy which prevents oxidation and buckling, and con sequently gives greater durability. The composition is said to consist of 94.5 lead, anti mony, and mercury.
Drake and Gorkam's cell has plates formed of roughened strips of lead laid horizontally one over the other, and connected by their ends to upright rods. From its construction this plate is free to expand and contract without injury to itself. Niblett's so-called " solid cell " has its electrodes separated by porous partitions.