371 



1858, June 23c?. At Milwaukee Station No. 1. 



This station is in a vacant lot near the north-east corner of Mil- 

 waukee and Mason streets. The intersection of the middle lines or 

 axes of these two streets, is 115 feet south of the parallel, and 107 

 feet west of the meridian of this observing station No. 1. 



The middle point of the base of the tall steeple of the Roman Catho- 

 lic Church on Jackson street, is by horizontal measurement, 545 feet 

 = 5". 38 of arc in latitude north of the parallel, and 557 feet = 7". 5 

 of arc = O5.5 of time east of the meridian of this observing station 

 No. 1. 



The observations made this night, for the latitude at this station, 

 were not conclusive. I obtained here 14 circum-meridian altitudes of 

 the star /3 LibrcB, culminating south of the zenith, but clouds prevented 

 observations on oe. Ursse Minoris (Polaris) north; therefore those on 

 /3 Librae were rejected, although they gave the latitude of this station 

 only 4". 6 less than it was afterwards made by a reduction to this 

 point, of satisfactory observations at stations Nos. 2 and 3, as will 

 presently appear. 



1. Observations for the Time at Milwaukee Station No. 1. 



Sidereal chronometer No. 2557, fast: 



By 10 observations on a Lyrse, east (at 157t. 42m. h. m. s. 



sidereal time) - - - - 1 00 43.5 



By 15 observations on « Bootis, west (at I6h. 08m. 



sidereal time) - - - - 1 00 42.52 



JReswZ^— Chronometer No. 2557, fast of sidereal time 

 for this station (at 15^. 55m. sidereal time, June 

 23d) - - - - - + 1 00 43. 



2d. The Longitude. 



The above determination of the time for this Milwaukee station, 

 and the time at Chicago, derived from the observations of June 22d 

 and 28th, already given, together with the comparisons of time for 

 the two places by the following telegraphic signals, give us the data 

 for the difference of longitude. 



The elapsed time between the two periods of observation at Chi- 

 cago, fixing the rate of mean solar chronometer No. 141, was greater 

 than I would have wished, but I could not diminish it. 



