Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER VI. Method of Obtaining Electric Current. There are three methods of obtaining the electric current. Of these methods, two generate the current as it is required, while in the third method the electricity is stored in a storage battery similar to the batteries used in the electric carriages, only much smaller. A battery of primary cells may be used, in which the electrical pressure is obtained by chemical means, due to the .consumption of zinc. Or the electrical pressure may be obtained by mechanical means, through the agency of a small dynamo or magneto-electric machine, driven by the gasoline motor. THE PRIMARY BATTERY. There are many forms of battery which are more or loss suitable for making the electricity that is used to fire the gas in a gasoline motor, but in the writer's opinion, the most satisfactory for this work are those wherein a solution of sal ammoniac serves as the active chemical agent. There are three types of cells of this description; the ordinary liquid form, the dry cell and the semi-dry cell. If the chemical agent is in a liquid state, the cell is undesirable because it is impossible to prevent the liquid from splashing out when the vehicle is driven over rough roads. This trouble does not exist in the dry cell, but this type of cell is usually very short lived because there is no circulation of the chemical agent, and that part nearest to the zinc plate soon loses its strength, due to its action on the plate. This defect is not apparent in the semi-dry cell because the chemical agent is in its liquid form, while it is prevented from spilling by the introduction of excelsior, cocoanut fibre, or some similar material to prevent the liquid from moving as a body. This form of cell is usually sealed with pitch, which further prevents the con...