REQUIREMENTS.--But on individual cars, incapable of getting current from a system of wiring, the matter presents an entirely different aspect, and brings forth new problems, hence storage batteries must be resorted to, and this involves the consideration of many elements that may be ignored with the usual traction system. Inventors have vied with each other to produce a type of battery that would possess at least three particular features of excellence, which may be stated as follows: First. Exceeding lightness, proportioned to the energy exerted, and compactness of structure. Second. A form of grid which will hold the matter, or active material, within it, and prevent it from disintegrating or falling out of the recesses into which it is pressed. Third. To add to the life of the battery, or to the individual grids, or plates, which means the discovery of new material, available to receive and accumulate the electric charge. GASOLINE-ELECTRIC TRUCKS.--Of late some progress has been made in constructing a type of electrics in which a gasoline engine is used, that is connected up with an electric generator. The latter is used to charge a storage battery also mounted on the truck, and the storage battery supplies the motor. The gasoline engine being connected with the electric generator is constantly in condition to charge the storage battery and may be set in motion, whenever the charge in the storage battery falls below a certain electro motive force. At other times the motor is at rest. In this type the electric motor is connected with the axle of the vehicle, so that it is always ready for service whether the gasoline motor is running or not. In the ordinary gasoline automobile it is essential that the motor must be maintained in service at all times, so that any derangement in that part of the system, which includes the mechanism intermediate the motor and axle, or the electrical devices, or the carbureter, means a dead car. It is urged that by combining the two systems a much wider range of usefulness will be obtained, and practice shows such to be the case. It has, however, some defects, one of which is the great weight necessary to maintain the entire train of mechanism thus described. The other disadvantage is the great first cost, although it is maintained that the decreased cost of maintaining the cars, while in use, is sufficient to warrant an increased cost in the selling price of the machines. It is undeniably true that such mechanism means additional care, and is liable to add to the complications necessary to operate the system, and it is obvious that these considerations will prevent the use of this type in all small vehicles, whereas it may be most serviceable and available in heavy trucks for transporting merchandise.