Total Eclipse of August 7, 1869. 179 



of the telegraph, its rate was ascertained to be fifteen se- 

 conds slower, daily, and the arc of oscillation a little shorter 

 than when running at the Observatory. On its return, 

 after being cleaned, it was again set up, when the rate was 

 found to be essentially the same as at Mattoon. 



Time. 



To Mr. Orton, the president, and Gen. Anson Stager, 

 superintendent of the Western Union Telegraph Company, 

 we are especially under obligations for putting a continu- 

 ous line of telegraph wire of nearly one thousand miles in 

 length at our disposal, for the purpose of securing time 

 from the Dudley Observatory. Our thanks are also due 

 to the managers of the following offices, all of whom were 

 interested in the success of the work: Mr. C. S. Jones, 

 manager of the Albany office ; Messrs. Hucker and Slacer, 

 Buffalo ; Messrs. Wright and Tindall, Cleveland ; Messrs. 

 Armstrong and Warren, Cincinnati ; Mr. J. F. Wallack, 

 Indianapolis; Mr. Patten, of Mattoon. The necessary 

 connections at the Dudley Observatory were made by Mr. 

 Thos. E. McClure and Mr. H. L. Foreman. 



A continuous circuit was secured on the nights of the 

 5th and 7th, when the Dudley Observatory sidereal and 

 mean-time clocks were compared with the clock and chro- 

 nometer at Mattoon. 



The mean daily rate of the clock was found to be 15.34 

 seconds slow. As the last comparison with the Dudley 

 Observatory time was only 5 hours after the eclipse, it is 

 presumed the time was very accurately determined. 



Chronograph. 



The chronograph used for the eclipse observations was 

 of the cylinder form, and was constructed expressly for 



