378 = S& P. Langley—Allegheny System of Time Signals. 
arrangement in a form adapted to the needs of American 
railways, and the supervision of their application to the wants 
of cities and individuals. 
In doing this, a great number of ingenious devices have been 
examined, and if the system to be described appears to be one 
of the simplest, it has yet been reached only after much care 
in setting aside all which would not bear the test of practical 
the Pennsylvania Central Railroad with its official standa of 
ime ; it the time is now sent daily to Philadelphia 0” 
the east, as far as Lake Erie on the north, and to Chicago on t 
west, regulating the clocks on a number of minor roads eo 
whose wires it goes, as well as on those of the principal soutl- 
ern lines connecting the Atlantic with the Mississipp!. Thus 
passing, as it does, over several thousand miles daily, 1 * 
elieved to be at present one of the most extended systems 0 
‘time distribution in the world. : 
The observatory is on the summit of the ascent on the north- 
ern side of the valley of the Ohio, about two miles in a 
