Velocity of the Galvanic Current in Telegraph Wires. 73 
given second. But whatever the velocity with which the clock- 
pause is transmitted,—or, in other words, however great an inter- 
val may elapse after the pendulum has broken the circuit before 
the pause is recorded on the register-fillet of a distant station,—we 
have as yet no means of detecting it; for in comparing the reg-- 
isters made at different places, this interval will (other things 
being equal) be the same for all the pauses, and therefore remain 
undiscovered. 
thirtieth of a second. ‘Then the clock-pause will be registered at 
Cambridge .,th of a second after it took place and was recor ed 
at Washington, and the arbitrary signal-pause will be recorded 
at Cambridge as soon as it is made, or ;/;th of a.second before it 
reaches Washington. We shall thus have the interval between 
ister will measure twice the time consumed in the transmission 
of the signals between the two stations. yas 
a 
23 94 25 26 
W. 
C. pig Eiihs 8 ae og cain Ae ee Se dete hay 
In order to avoid accidental errors, the mean of many measure- 
ments may be used,—and half the mean excess of the interval 
between a clock-pause and the next succeeding signal-pause gives 
Us the time occupied for the transmission of a signal. 
' : he one consists of the electrotome, or br Ie 
of the circuit: the other is the restoration of the circuit, or elec 
ss | 
ginnings of the pauses,—be- 
tween the elect s. or beginnings of the lines,—or as being 
: inenstive i niddle of one pause to the 
le of the next. Mr. Walker has used the latter, the mean of 
Brees 
: * Astr, Journ, i, p. 51. 
s, Vol. XI, No, $1.—Jan, 1851. | 
ee a 
10 
the signal-pause and the preceding clock-pause longer at Wash- — 
- ington than at Cambridge, and the excess on the Washington reg- — 
