Gould's Report on Trans-Atlantie Longitude, 229 
longitude—Talcott’s for the one, and the Telegraphic for the 
other; the former, devised in 1834, giving us in a single 
night's work with the zenith telescope, or a transit instrument 
used as such, the latitude to a small fraction of a second, and 
the latter, the longitude, also, for the first time in the hi f 
geodesy, with corresponding facility and precision—a facility 
and precision, taken together, wholly unattainable by other 
methods, and in the case of longitude especially, unapproacha- 
ble even, particularly in extended operations. 
It was not till some years after the telegraphic method had 
been well elaborated here, and in successful use, that it received 
much attention abroad; and even then, the modes of practice 
recommended as original, by even eminent astronomers, partic- 
ularly in France, were only such as had been long employed in 
our Coast Survey, or superseded by better, and had been pub- 
lished to the wenle repeatedly, and through various channels. 
Almost simultaneously with the invention of the telegraph 
must have occurred to astronomers the idea of using it m de- 
termining longitudes. It was natural enough, therefore, that 
the best methods yet devised of determining both latitude and 
i 
in 1844, by 
comparison of chronometers at the two termini. The experi- 
the Coast S ractice, almost exclusively, from the first. 
Dr. Gould succesded Mr. Walker in 1851; and in the wale 
to a very high degree of efficiency, and, with his aids, ca uh 
“¢ and them for the difficult task, the history and results of 
which are set before us in this Report. Pee 
Dr. Gould’s paper contains cacker’ cha’ 1 —_ = 
Coast Survey ition; 2, Previous eterminations : eas 
trans-Atlantic longitude; 8, History of the econ 6, 
servations at Valencia; 5, Observations at Neti? a 
Observations at Calais; 7, Longitude-signals between #0 
