880 S& P. Langley—Allegheny System of Time Sigdals, 
consists less in this, however, than in a device by means 0 
which it can be caused to gain or lose any fractional part of 4 
change is being effected. This chronometer is to replace the 
nection with the local circuits of the observatory ; one ba 
bang employed for the sidereal clock and chronograph, aly 
another for the mean-time standard. Any interruption of the 
when the circuit is opened. The accessory apparatus, suc ie 
batteries, relays, switch-boards and so forth, which are use 
in every telegraph office, it will be superfluous to describe here 
1ethod which has been adopted as likely to ensure ™ 
accuracy in the time keepers which control it. : 
