A Novel Fire Alarm.

A Novel Fire Alarm.

A novel system of fire alarm signals by rocket bombs has been established in the suburban districts of San Francisco to enable the remote engine houses quickly to summon assistance from the city forces in case of great emergency. A bomb, something like a rocket, is thrown 300 feet straight upward from a mortar, where it bursts, making a brilliant white light and a very loud explosion. At the trials of the system a week or so ago all San Francisco was excited and alarmed, fearing dynamiters were at work. The system is arranged so that the precise locality where aid is needed is made known.

A Novel Fire Alarm.

0

A Novel Fire Alarm.

A novel fire alarm has lately been produced in France. It consists of a hollow sphere of aluminum supported at one end of an arm, with a counterpoise at the other end, the two being arranged to balance at the ordinary temperature and pressure of the air. The apparatus is not sensitive enough to record natural changes of pressure, etc., but if some unusual cause, such as fire, or even a large accumulation of coal gas in the atmosphere, disturbs the specific gravity of the air, the ball drops and rings an electric alarm in falling.