398 Lieut. Davis on the Prime Meridian. 



be found having this suitable difference of meridian of six hours, 

 or one quarter of the circumference, from our present standard 



meridian of Greenwich. 



This choice has other recommendations, which give it the 



preference over Washington. The meridian of the latter cuts 

 the coast between Cape Fear and Cape Lookout. Our coasting 

 vessels, and domestic packets, therefore, in going and returning 

 between our northern and southern ports would be subject, if it 

 were taken, to the inconvenience of a change of name in the lon- 

 gitude, which, as is well known to navigators, always involves a 



liability to error. 



The meridian of New Orleans on the other hand, is so far west, 

 that all the longitudes on the Atlantic coast remain on the same 

 side. It is only on the coast of Louisiana, west of New Orleans 

 and of Texas, that they change. This change takes place where 

 the river Mississippi empties its turbid waters into the Gulf, where 

 nature has marked the line by an altered condition of the water, 

 such as may be observed by the careful seaman at some distance 

 from the land. 



Another practical recommendation of this choice is this : If 

 New Orleans be adopted, then between the American and Eng- 

 lish meridians, the degrees and minutes on the chart will be the 

 complements of each other. To the westward of the American 

 meridian, up to 180°, the minutes will be the same, the degrees 

 being less by 90°. To the eastward of the English meridian 

 there is the same advantage ; the number of degrees on our part 

 being greater by ninety, up to 180° of the English longitude. 

 Between the inferior meridians of the two nations for the space 

 of 90°, the sum of the American and English longitudes will be 

 equal to 270°, but they will be of different names. 



These normal differences are easily remembered, and compare 

 favorably with the confusion that will follow, if the modes of 

 reckoning longitudes by the two nations differed by so unmanage- 

 able a quantity as 77° 04'. The time is not distant when we 

 shall have published, under the authority of the government, per- 

 fect charts of our harbors and external sea-coast. I trust also that 

 the day is not far distant when foreign charts (improved by sur- 

 veys made by our own officers) will be issued from the bureau of 

 Hydrography of the Navy Department, for the benefit of the 

 commercial marine of our own and other nations. These charts 

 should be rendered as serviceable and available as possible to the 

 whole maritime world; and this end will be attained in the man- 

 ner pointed out above. What is for our own advantage will prove 

 beneficial to others. 



lyof 



It may be proper to observe here, that although I speak only 

 the meridian of New Orleans as arbitrary, yet all prime meridians 

 are essentially arbitrary. They have been selected always with 

 a sole reference to the national convenience. Some nations, as 



