ABSTRACT
The survival of the hot tube in both gas and petrol-engines was due to the ineffectiveness of the apparatus for producing an electric spark. The petrol-engine is par excellence the engine for small powers, and it attracted attention from the first by reason of its extreme lightness. In the earlier petrol-engines the valves were almost universally of the poppet type or mushroom shaped, and it is almost impossible to avoid a certain amount of noise when these are rising and falling nearly a thousand times a minute. The cost of light oil—petrol or gasoline—led to the attempt to design engines which would burn a cheaper fuel, and Priestman, of Hull, put such a one on the market in 1888. The small oil or petrol engine is admirable for domestic purposes, such as driving a vacuum cleaner, or pumping water and driving a dynamo to light a house that is far from a town supply.
