This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
The usual way to provide for a sure supply of water to flush out the closet has been to fit up over it a copper-lined tank supplied from the house service and regulated by a ball cock. The operation of flushing the closet is performed by pulling a chain or rod which raises a heavy plug from the upper end of the flush pipe and causes a more or less prolonged flow of water, when the plug again seats itself and the tank is refilled. (Fig. 51.) This simple operation in itself is productive of considerable noise and there are on the market many devices aimed to secure an ample flow with a minimum of noise. Another form of tank, and especially valuable where height is limited is called the "low down" tank. (Fig. 52.) In these the loss of power of gravity is made up by enlarging the supply and they are very satisfactory in their operation. A newer and increasingly popular form of flushing closets is by means of a valve which delivers a quantity of water directly from the general service, or from a special supply, and then closes automatically.
Fig. 50. Washout Closet.
Fig. 51. Common Tank.
Fig. 52. Low-Down Tank.
These valves are put upon the market by different dealers under various names, but are about all identical in principle. These valves have been formerly used where many closets are to be supplied or where the presence of any kind of tank is undesirable, but. are coming more into favor for general usage.