Improvements of the Faure type are, generally: (1) Those which have for their object the retention of the paste on the plate ; and, (2) those intended to provide better connection between the support and the active material.
For the retention of the paste, instead of perforations, grooves or recesses have been made on the surface, or the plate is cast with projections from it so as to afford a lodgment for the active material. The Tudor plate (see below) is an instance of this type.
The construction of a mold to produce a perforation expanding inwardly is a difficult matter, and therefore the grids are cast in two halves and subsequently joined, as in the Gado/ cell, Fig. 5. In the Correvs cell, Fig. (3. much used in Germany, the grid has the form of a double lattice. In the Roberts cell. Fig. 7, two grids are used, pasted on the side and then united to form a plate with the paste inside.
The Totanwsi multtlabular storage battery (Fig. 8), invented by Dr. Donato Tommasi, of Paris, has each electrode formed of a perforated tube, or folded sheet, closed at one end by a small plate of insulating material, into which is screwed a rod. The rod. which serves as a support for the tube eke troth', is provided with a suspension head, which also serves as a contact. Instead of cylindrical tubes, prismatic ones may be employed, as in Fig. 8. utilizing the space to better advantage. In the annular space between the tube and the contact conductor of each electrode the active material, spongy lead, or lead oxide, etc., is packed. BO that the tube serves only as a support for such matter, and can he made of tiny substance desired, so long as it is not attacked by the acid.
ltegnier's high voltage elastic accumulator was designed to afford a single compact structure, having the qualities of high voltage, solidity, and portability. As shown in Fig. 9, it has sixteen plates monnted in flexible pockets. These elements are placed flat one against the other, and compressed between two end plates of wood by means of rubber bands. A bridge consisting of hard wood impregnated with a water proofing, material carries the whole, which may be suspended, or rest upon its base, as desired. This arrangement gives to
the active solid matter an artificial elasticity which results in large specific power and storing capacity. This continuous compresQiou of the plates, etc., gives protection against rough handling.
The Desmazures storage battery (France) has its electrodes composed of amalgamated Zinc plates and porous copper plates, the latter tieing produced by the consolidation of powdered copper under very great pressure. The zinc plates form the negative electrode and are in metallic connection with the box, which is also of zinc, while the positive plates are placed in vegetable parchment bags and suspended in the usual way. Contact with the negative plates is prevented by glass rods. The electrolyte is a mixture of chloride of sodium and a caustic solution of zinc oxide.
The Tathine accumulator (Brussels) is of the Plante type, in which the liquid consists of a satu rated sulphate of zinc solution, to which is added 51) per cent. sulphuric acid, 5 per cent. of sulphate of ammonia, and 5 per cent. of sulphate of mercury. In making up the cell, the ingredients are poured in in the reverse order to that given here. The addi tion of the sulphates of mercury and ammonia is said to prevent the formation of sulphate of lead on an open circuit. The E. M. F. of the cell is given as 2-3 volts.
The use of IAthanode as an active material in the anodes of storage batteries has been advocated by Desmond G. Fitz-Gerald. This substance is peroxide of lead in a dense, coherent, and highly conductive form, and is obtained by a patented process. its chemical composition is almost identical with the active material generally used, but it is different in molecular constrnction, and free from liability to local action. A. V. Meserole, of New York City, has found that an electrolytic sponge composed largely of mercury and zinc with some lead, in combination with a plate of peroxidized lead, produces a very efficient storage battery. By using the same material differently combined and formed, radically different results are obtained.