386 SS P. Langley—Allegheny System of Time Signals. 
from its commencement will, it may be hoped, justify the belief 
that its use has proved not only valuable to railways, but an 
added security to the safety of the public. 
3d. Supply of time to cities. At present, arrangements 
are in progress for regulating the principal public clock of 
Pittsburg, (the turret clock of the City Hall, about two miles 
om the observatory), which it is intended shall strike every 
third hour on the bells of the fire alarm, and probably also in 
the various police stations. As the mechanism for doing this 
is still in course of construction, and may yet be modified im 
trial, it would be premature to speak of it, especially as its suc- 
cess has not yet been proven in practice here. The city clock 
will automatically report its own time to the observatory by a 
special wire, and it is probable that in controling its rate from 
the observatory, the “Jones” system will be used. 
The necessity of a uniform standard of time over the whole 
country, which was alluded to in the outset as one of growing 
importance, has not been further directly touched upon in this 
article, which is yet as a whole devoted to describing the means 
of meeting it. The evident tendency, in thus sending the tme 
from one standard over so large an extent of territory, to 
diminish the number of local times, and so prepare the way for 
a future system, in which, at least between the Atlantic and the 
Mississippi, they shall disappear altogether. 
step in this direction has been contemplated by the a 
gers of the roads uniting New York, Philadelphia, Pittsburg 
and Chicago, who have intended to use the time of the ge 
ian of Pittsburg between the two extreme points mentiones; 
running all trains from New York to Chicago by this ae 
alone, in place of using successively the local times of Philadel- 
hia, Altoona and Columbus, as at present. Such a change 
would have already taken place during the last summer, eX°¢ ' 
for an unexpected cause of 
effected. ; 
The labors of this and of other American Observatories at 
tending to the same important end, that of the ultimate adop- 
tion of some single time for all the country east of the Missis- 
sippi, by which not only the railroads, but cities and the publie 
generally, will regulate themselyes. What point shall be chose? 
is of less importance than that some one shall be used and Un — , 
versally. : 
The subject is one which has hitherto attracted little public 
attention, but it does not seem unsafe to make the assertloPs 
that the causes which have almost insensibly effected such ® 
-siclbseag in England, will in a few years more bring it about 
re. 
Allegheny Observatory, Allegheny, Penn., Sept, 22, 1872. 
