On the Electric Telegraph of Prof. Morse. 59 
le and LB represent the local circuit and battery, M the helices of 
the register magnet included in this circuit, which, as the stand- 
ards s, s, are metallic, is broken only at the points a, 6. Now the 
least possible space between these points effectually interrupts the 
current, and as they are covered with platinum, a very slight con- 
tact is sufficient to establish the connection. The little instrument 
is so delicately adjustable, that often when the breath could stop 
the vibrations of the lever, the circuit is broken and closed with 
certainty and regularity. The points are carefully kept free from 
dust, and the lever is adjusted by the elasticity of a spiral spring 
With its silk thread attachment. Very much of the operator’s 
differs essentially from the same agent in the laboratory. ‘The 
if separated each night, fresh acids, but once in five or six wee 
action, has afforded a uniform current for two weeks without 
separation. | opie art 
The numerical extent of the series seems principally to give 
efficacy to the battery. It has worked competently with acids 
reduced almost to water and with metals scarcely imme peed 
a 
