68 



as the basis of the comparisons, a similar process to the above, will 

 give us the following additional results, viz. — 



(c) By mean solar chronometer No. 141 : Fulton m. s. 

 west of Chicago, - - - +10 08.96 



(d) By sidereal chronometer No. 2557: Fulton west 

 ofChicacTo, - - - - - + 10 09.15 



Mean of the 4 results, a, ^», c, ^, - - - -j- 10 09 04 



Longitude of Chicago observing station No. 1, + 5 50 30.99 



1st Determination, 

 Longitude of Fulton observing station, by the run of 

 the two chronometers, west of the meridian of 

 Greenwich, - - - - - 6 00 40.03 



On this journey, the chronometers were transported in the rail 

 cars. Each chronometer was carried in a small basket, resting within 

 a nest of elastic curled hair, with a lining of soft green baize between 

 the hair and the chronometer. Every pains was taken to protect 

 them from jolts and all kinds of rough usage. From long experience, 

 I believe that good results for differences of longitude, derived from 

 transporting chronometers, depend much more upon this sort of care 

 and attention to them, than upon any other circumstances attending 

 the operation. A few seconds of time are easily lost by careless 

 handling of the chronometers. 



In the present month of June, 1859, 1 determined to test the above 

 result for the longitude, by the method more recently followed, of 

 transmitting time-signals by the electric telegraph. 



For this purpose, the time-observations of Chicago, given under the 

 dates of June the 22d and 24th, and those now to be given under the 

 date of June 23d, together with the signals, were made. 



1859, June 2M. At the Fulton Observing Station, already 

 described. 

 Sidereal chronometer No. 2557, fast: 



Is^ Set. Before the Signals. 

 By 8 observations on « Lyrrc, east h. m. s. 



(at 15/i. 20m.) - - - 1 51 04.00 



By 12 observations on « (12) Canum 



Venaticorum,wcst(atlC/i.OO///.) 1 51 04.21 



