4th. Both standcocks being opened, the farthest one gave a jet of 23 feet, and delivered 58 gallons per minute.
When both these plugs were allowed to flow freely without hose, the water from that nearest the large main, rose about 18 inches, and the farther one about 1 inch above the plug-box.
Fig. 7. Common Fire-plug.
These and other experiments prove the necessity of placing the plugs on the mains, and not on the service pipes, where there are mains in the street.
The different modes of obtaining water from the mains or pipes are shown in the accompanying drawings.
(Fig. 7) is a section of a common plug when not in use.
