364 



Determination of the difference of Longitude between Chicago and 

 Michigan City, Indiana, by electric signals for comparisons of 

 time, June 2ist, 1858. 



Sidereal Chronometer No. 2557, flist, of Michigan City, sidereal 

 time, (at 16//. d7?n. sidereal time,) + 567n. 31s.22. 



Rate per sidereal day, + 65.05; or per sidereal hour, + 0s.250. 



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

 tUTfie, (at 10//.. 54m. mean time,) — 4m. 58s.68. 



Rate per mean solar day, + 0.37s; or per mean solar hour, + 

 0s.015. 



1st. — Chicaso signals recorded at both stations. 



1st Mean. — Electric signals sent from Chicago to Michigan City, 02 53.763 



2d. — Michigan City signals recorded at both stations. 



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



Ist Mean. — Electric signals sent from Chicago to Michigan City, 



as above, -._._. 



Result : — Michigan City Observing Station, east in longitude of 

 Chicago observing Station No. 2, by a mean of the two sets 

 of signals, .-..-- 



02 53.713 



02 53.76 



02 53.74 



