The Deane switch valve is a device by which compound low service pumps may be converted into powerful fire pumps. This appliance consists of a valve of such construction that steam may be allowed to enter the cylinders as usual for compounding, or may be diverted by simply moving a lever, when all four cylinders receive steam at boiler pressure, each exhausting independently to the atmosphere. The change makes each steam cylinder available for its maximum power, all four cylinders develop their full power, and its effect can be utilized in powerful fire streams. It should be borne in mind in justice to the manufacturers that the Deane switch valve is not to be classed with the ordinary two or four-valve arrangement, which, while admitting initial steam to the second cylinders, develops no power in the first, or, as it is sometimes arranged, uses initial steam in all four cylinders and develops less power than if the second cylinders were used independently. This valve is recommended by the Insurance companies, and compound duplex pumps fitted with the Deane switch valve will be accepted in place of the Underwriter pump of similar capacity. This valve is also frequently used where two widely differing water pressures are required for other purposes than for fire protection. Every machine is subject to rigorous tests before leaving the factory, including a 300-pound test of the water cylinders. Every pump is guaranteed to be in full accordance with the specifications. UNDERWRITER FIRE PUMPS. The Insurance Companies have issued detailed specifications for the construction of fire pumps to be known as Underwriter Fire Pumps. They have agreed that such pumps with their specified attachments be recognized as the approved type, and that pumps built and fitted up less perfectly be not approved in future installments. _The wide experience and systematic methods_ of the Insurance Companies place them in position to give valuable suggestions as a result of their observation and experiment, and these are embodied in carefully drawn regulations issued by their Engineering Department. The specifications are very exacting in every particular, entering into _the design, material, and workmanship in minute detail_. They call for a number of fittings and attachments not usually furnished, and a most rigid test at the factory before shipping, and by the Inspecting Engineers of the Insurance Companies after the pump is installed, which secures for the purchaser the certainty of having a machine which beyond any reasonable doubt can be relied upon to do its full duty when emergency arises calling for its use.