and its application to Fire Alarms. 73 
obtained hy the action of the Key-board, which communicates 
he same Signal in succession to the different Circuits. - 
In connection with each of the Alarm Circuits, as they pass 
out of the Central Office, is an Alarm Bell Register for indicating 
the number of Electric impulses sent over the wires, and the 
corresponding number of blows struck upon the bells by the 
hammers of the Striking Machines. In form it is similar to a 
register in use for other purposes. The movement resembles that 
of Mr. Farmer’s electro-magnetic clock. ‘There are three cylin- 
ders, seen partially in the figure, 3 
whose circumference is divided 
decimally and marked with fig- 
ures, representing in their place, 
impulse of the current moves ALARM BELLS 
figure, at every tenth impulse A 
moves the cylinder of tens also | 3 (4.04 
forward one figure, and at every 
hundredth impulse moves the 
one figure, 
the others. The indications of FQ Q 
. . | ae 
tant in connection with ma- > 
chines carried by weight. Thus, ' ape 
it alarms are very frequent, the Alarm Bell Register may show 
that the striking machines require to be wound up in anticipa- 
Hon of their regular time. 
It is essential to have systematic. means of testing all the Cir- 
cuits, employed in the Fire System. Where a closed Signal 
itcuit is used, an interruption from any cause, gives of itself a 
Signal at the Central Office. Where an open circuit is used, as 
it is, in connection with the Alarm machinery, or may be, in con- 
Hection with the Signal apparatus, other means must be em- 
only. 
Md ni 2 3) 
ws 
