192 Prof. Lovering on the American Prime Meridian. 
counted from an American prime meridian. The importation of 
a prime meridian from Europe to our own territories will not, I 
conclude, operate for the improvement of our navigation. 
Neither do I believe that our knowledge of American geogra- 
phy will be advanced by an American prime meridian. ‘The 
longitudes of a large number of places in the United States have 
already been determined with great accuracy by the usual astro- 
nomical methods or by the transportation of chronometers; and 
the relative differences of longitude between the principal spots 
on our coast and those cities and observatories whose longitudes 
are best known will be assigned through the operations conducted 
by the excellent superintendent of the U. States Coast Survey. 
Were all our longitudes to be calculated from observations of 
eclipses, occultations or transits, so rapidly is the number of o 
servatories and observers increasing over the whole country, there 
is reason to believe that the capital places in all the states and ter- 
ritories would be determined in this way, if not with absolute 
precision, with all the accuracy that is wanted for the construction 
of a correct geographical map of the United States. In this case, 
owever, not only might the absolute distances from Greenwich 
slightly fluctuate, but the relative distances from each other also. 
For we could hardly expect that the longitudes of all these places, 
as measured independently from Greenwich, would be determin 
with equal precision. We should rather suppose that the meridi- 
ans most remote from Greenwich and less crowded by population 
would not, in general, be projected so carefully as the nearer an 
older meridians. But the transportation of chronometers from 
place to place will give our relative longitudes independently of 
any uncertainty as to the exact distance between the eastern and 
e permanent. Moreover, the superintendent of the U. States 
coast survey has applied with triumphant success the admirable 
telegraph of Professor Morse to the determination of the long! 
tudes of places intersected by the telegraphic wires. The coun- 
try is already traversed, in every direction, by the grand tele- 
graphic lines, and these will be crossed in a few years, at a mul 
titude of points, by a finer network. If we wait this short time, 
our relative longitudes will be ascertained with a precision, @ 
simplicity and an economy wholly unprecedented as yet in the 
scientific history of any country in the world ; and without any 
reference to our first meridian, whatever it may be. ‘The map 
and the meridians upon it will never fluctuate. The floating 
error to the extent of half a mile in regard to the exact distance 
