372 



Determination of the difference of Longitude between Chicago and 

 Milwavhee, hy electric signals for comparisons of time, June 



2M, 1858. 



Sidereal Chronometer No. 2557, fast, of Milwaukee, sidereal time, 

 (atllh. 39m. sidereal time,) Ih. 00m. 43s.46. 



Rate per sidereal day, + 66'.14 ; or per sidereal hour, + 0s.251. 



Mean Solar Chronometer No. 141, slow, of Chicago, mean solar 

 time, (at 11^. S2m. mean time,) 4m. 57s.51. 



Rate per mean solar day, + 05.76 ; or per mean solar hour, + 

 Os.0317. 



1st. — Milwaukee signals recorded at both stations. 



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



01 06.81 



2d. — Chicao-o signals recorded at hoth stations. 



2d Mean. — Electi'ic signals sent from Chicago to Milwaukee, 01 06.83 



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



above, - - - - - - - 01 06.81 



Result: — Milwaukee Station No. 1, west, in longitude of Chicago 



observing Station No. 2, by a mean of the two sets of signals, -j- 01 06.82 



