51 



Determination of the difference of Longitude between Chicago and 

 Erie, Pennsylvania, by electric signals for comparisons of time, 

 August 9th, 1858. 



Sidereal Chronometer No. 2557, fast, of Erie, sidereal time, (al 

 20//. o9m.. sidereal time,) Sim. 02s.81. 



Rate per sidereal day, + 5,9.62; or per sidereal hour, + Os.234. 



20, mean solar 



Mean solar Chronometer No- 141, slow, of Chica 



tli^U, 



time, (at ll/t. 15m. mean time,) Am. 29s.67. 



Rate per mean solar day, + Os.455; or per mean solar hour, + 

 Os.01896. 



1st. — Chicago signals recorded at both stations. 



1st Mean. — Electric signals sent from Chicago to Erie, 



30 09.708 



2d Mean. — Electric signals sent from Erie to Chicago, 



1st Mean. — Electric signals sent from Chicago to Erie as above, 



Result: — Erie Observing Station is east, in longitude, of Chicago 

 Observing Station No. 3, by a mean of the tvro sets of 

 signals, ------- 



30 09.722 

 30 09.708 



30 09.715 



