Evening star. [volume] (Washington, D.C.) 1854-1972, 1908-07-26
ELECTRIC SOUND SIGNALS
TRUMPET BLOWN WITH FORCE
BY THE MYSTERIOUS AGENT.
Siren Makes Powerful Noise and
Uses Little Energy-Sundry Ad-
vantages Over Bells.
From Current Literature.

| From Current Literature.
| trumpet designed to give d SOUND
| signal ,bv electric action has been de-
yised in Germany, and is likely to fine
extended use, replacing in great part
the present electric bell or "buzzer.'
Writes DR. Alfred Gradenw!tz, descrlb-
ing the new invention in Cosmos:
."rhe need has been frequently felt
during recent years of device Tor CIV
ing sound signals that will be heard
above disturbing noises in whose pres
| ence ordinary alarms are without Ell
| feet.
An electric siren which appears &c
satisfy this demand perfectly has been
constructed by the Deutsche Telephon-
werke at Berlin.oIn this apparatus the
| armature of an electromagnetic, excited
| by a variable current of determlnate
| frequency acts on metallic membrane
| through lever. The ratio OF the
| lengths of the lever arms is so chosen
| as to secure a strong and powerful
| sound
"The sounding membrane which is
| relatively solid is made Of an alloy OF
| nickel bronze; it closes the apparatus
hermetically. The mechanism is con-
| tanned in a gas and water proof box
and consequently the device may be In
|
special protection.
The electric siren uses d very small
quantity of energy. while its acoustic
performance is greatly superior to that
| of ordinary annunciators or bells
Sirens Good Points.
"A special advantage of these devices
| is the facility with which several of
them are arranged in parallel and con-
trolled from central point by an
| ordinary contact button The arrange
ment Of connections is about the same
as with ordinary annunciators.
"'The electric siren is easily used for
| giving all sorts of well defined signals
analogous to those of the Morse alpha
bet Among these numerous applica
tions the following may be cited as
most important:
An evident field of application is for
systems of fire alarm. AS the sound of
the siren resembles exactly that of the
alarms generally used. the character of
the signals will be clearly ineligible
to every one.
Alarm Systems.
This device may be employed to ad-
vantage in alarm systems on board
vessels, where it may take the place OF
various kinds of annunciators and bells
now used to give orders to guards sta
toned in the different compartments,
or signals to engineers, firemen or
pilots These orders are transmitted
simultaneously to all the compartments
in question by pressing on one contact
button, which evidently assures great
economy of time in case Of imminent
danger.
Another possible application relates
to railways, where the device may be
used to give all kinds of signals on the
| Morse system with as small eX-
penditure of energy as possible.
| ."rhe apparatus is also adapted to
| aired uses in mines to con-
| troll the underground cableways, ETC.
and to give fire alarms, either within
| the mine or outside.
I'm similar fashion 1T may be used In
the system of annunciators of a bank
| ing house or office building. Finally II
! may be employed as signal on auto
| mobiles and motor boats"