482 ' Royal Astronomical Society. 



" 3rd. The sevenfold multiplication of observations in the same 

 interval of time, or in the single transit of one, or the relative trans- 

 its of two or more heavenly bodies. 



" From all these sources it will be apparent that Mr. Walker's 

 method of printing dates has nearly a tenfold advantage over the 

 ordinary mode of using the transit instrument. 



" A single transit of a star, or a night's or even a year's work by 

 this method of printing, may take the place of some ten times those 

 quantities by the method now in use. 



" The experiment of printing the dates of bisections of transit 

 wires by a star, on the ordinary registering fillet of Morse's telegraph, 

 was made by Mr. Walker in 1846. It was repeated this last summer 

 for some twenty or more stars, in connexion with Prof. Bond and 

 Prof. Loomis, for a distance of some three hundred miles from Cam- 

 bridge to New York. In October last it was repeated for a like 

 number of stars between Philadelphia and Cincinnati, in connexion 

 with Prof. Kendall and Prof. Mitchell, through a distance of seven 

 hundred and fifty miles. The taps made on the telegraph key at 

 the time of bisection at each place were registered at both. In these 

 operations, however, the year was used to estimate fractions of a 

 second by the audible beats of the telegraph and observing clocks, 

 and no use was made of the visible register. 



" Dr. Locke's electro-magnetic clock of his own invention and 

 construction (Wheatstone's method not being known to him at the 

 time) was used for some two hours or more, on the 17th of November 

 last, to make the automatic clock register such as is described above. 

 The distance tried was about four hundred miles from Cincinnati to 

 Pittsburg. 



" The experiment was completely successful. The interruption 

 of the line from Pittsburg to Philadelphia that night prevented the 

 actual continuation of the two operations on the same fillet of paper, 

 namely, the graduation of the paper by the automatic clock, and the 

 reciprocal imprinting of the dates of transits of stars at the two ob- 

 servatories. Each process, however, has been tried by itself to a 

 sufficient extent by Mr. Walker and his associates, to warrant his 

 conclusions with respect to their combination, for a more full trial of 

 which he now waits for the construction of the most approved ap- 

 paratus. 



" In order to make the precision of the other ajjpendages of a 

 transit instrument commensurate with the tenfold increase of that of 

 the art of imprinting the dates of bisections for a single culmination, 

 Mr. Walker recommends the use of a cast-iron box for the frame. 



" Each side should carry three or more levels. 



" The number read on each occasion should depend upon the 

 degree of precision aimed at. The instrument should admit of rapid 

 reversal, even on equatoreal stars. For use at the station of the 

 Coast Survey, Mr. Walker prefers to retain the micrometer adjust- 

 ment of the azimuth, like that of the new Simms's transit instru- 

 ments recently made for the survey. 



" In the telegraph operations for longitude, two such transit in- 

 struments of moderate size are to be mounted, at any two stations. 



