112 



This result, and the results of the time-observations made at 

 Chicago on the 16th and 19th* of May, and the following telegraphic 

 signals, give us a third determination of the longitude of Michigan 

 City, as follows, viz — 



Determination of the difference of Longitude between Chicago and 

 Michigan City, by electric signals for comparisons of time, 

 May 17//t, 1859. 



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

 time (at 14/j.. 11m. 12s. sidereal time), lA. 33m. 29s.89. 



Rate per sidereal day, — 7.9.366 ; or per sidereal hour, — 0s.307. 



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

 time (at \0h. 27m. mean time), 4m. 41s.02. 



Rate per mean solar day, + 05.377; or per mean solar hour, + 

 Os.01.57. 



1st. — ChicajTo signals recorded at both stations. 



1st Mean. — Electric signals sent from Chicago to Michigan City, 02 53.577 

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



2d Mean. — Electric signals sent from Michigan City to Chicago, 02 53.55 

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



as above, - - 02 53.577 



Result: — Centre of Public Sciuare in Michigan City is east, in 

 longitude, of Chicago observing Station No. 3, Ijy a mean of 



the two sets of signals, 



— 02 53.56 



It was cloudy at Chicago, May 18th, and uo obBervations could be made ou that uight. 



