396 Lieut. Davis on the Prime Meridian. 



this purpose by the late Dr. Bowditch, and communicated to the 

 American Academy, bear the marks of his genius and labor. 



The means of determination have since been greatly multiplied 

 •solar eclipses, occultations, and moon culminations, have been 

 collected in great numbers. The transportation of numerous 

 chronometers between England and Boston has afforded the ma- 

 terials of further improvement. Commodore (now Admiral) 

 Owen, whilst engaged in the survey of the Bay of Fundy, car- 

 ried his chronometers to Boston, adopting that as his American 

 first meridian, because it was the best determined. Mr. Bond, 

 the Director of the Observatory at Cambridge, has been for sev- 

 eral years, employed in the service of the government, in accu- 

 mulating all the means of perfecting the longitude of Boston. 

 Yet I am informed, that there still exists an uncertainty in this 

 longitude, notwithstanding all the labor and care bestowed upon 

 it, to the amount of, perhaps, two seconds of time. It is, also, a 

 pregnant fact, worth mentioning, that the relative longitudes, even 

 of the Greenwich and Paris observatories, have been recently 



changed. 



But the uncertainties arising from the intrinsic difficulty of 

 making absolute determinations of longitude increase as the place 

 is more remote, and therefore less known or cared for. The as- 

 sumption of a new origin of longitude situated in this country, 

 will, to a considerable extent, remove these uncertainties, and 

 save us from those fluctuations in our geographical positions to 

 which we are now subject. In the magnetic telegraph we have 

 a means of determining differences of meridians, which belongs 

 to the highest order of accuracy. It can be applied at once 

 wherever the wires now run. An American prime meridian be- 

 ing adopted, this should be done as soon as possible. As the use 

 of the telegraph is extended, the interior, throughout its whole 

 space, would be connected in this manner with the stations of 

 the coast survey and the national observatory, and would have 

 the geographical positions of its chief cities and county towns 

 permanently and unalterably fixed, and thus the foundation would 

 be laid of a correct geographical map of the whole country 



In making a change, however, that is so radical with regard to 

 some of our citizens and their pursuits, great consideration is to 

 be had, I think, for their practical wants and conveniences. 

 These last should be no farther sacrificed than the first demand 

 of an independent accuracy strictly requires. Our navigators and 

 seafaring people generally, are chiefly concerned in the result of 

 this change. Speaking a common language with the greatest 

 commercial nation of the world, our own vessels are constantly 

 meeting those of Great Britain on the highway of nations, and 



are in the habit of comparing with them their longitudes. From 

 this facility and frequency of intercourse they receive and confer 



