56 SURVEY OF MASSACHUSETTS. 
would seem, therefore, a matter of course that the difference of their longitudes should, 
long since, have been ascertained; yet, principally on account of the difficulty above 
mentioned, so late as the year 1775, a century after the establishment of the former, the 
supposed difference was erroneous by five and a half seconds of time; as it was then 
considered 9" 16°; in 1780, Gen. Roy deduced from the trigonometrical survey of Eng- 
land, made under his direction, 9" 18'.8; thirty-five years ago 9" 20° was used; and within 
a few years from observations on about one thousand transits of the moon and a star, 
and many on the explosion of rockets, 9" 21.5 was deduced, which is the quantity now 
used, 
As the place from which longitude shall be reckoned is altogether arbitrary, it follows, 
as might have been expected, that different nations have fixed upon different places for 
the first meridian. 'Thus the English universally, and the Americans generally, reckon 
from the observatory at Greenwich, the French from that at Paris, the Germans from 
Berlin or Ferro, the Spanish from Cadiz, &c. It is much to be desired that some one 
place should be generally agreed on, and nothing but national prejudice has hitherto 
prevented the attainment of this object. It is highly probable that Greenwich will 
eventually be considered the first meridian, as already the two greatest commercial 
nations of the earth reckon from it, and as the observatory there has long been by 
common consent pronounced the most important and distinguished. Indeed, an eminent 
and gifted astronomer of France has remarked of the observations made at Greenwich, 
that if by a great revolution the observations made every where else were lost, and those 
only should be saved, there would be found in them materials sufficient to rear anew 
almost the entire edifice of modern astronomy. 
I am well aware that in a few American maps the capitol at Washington has been 
adopted as the first meridian, for no other reason than that it is the building in which the 
national congress assembles. ‘This step appears to me to be highly injudicious. The 
number of first meridians is not only thus increased, but the position of that building is 
not by any means well ascertained; indeed, from the observations made in its vicinity, 
on the annular eclipses of the sun of 1791, 1811 and 1831, I have deduced for its longi- 
tude a quantity greater by more than siz miles than that usually assigned to it. 
Moreover, if we consider Greenwich as the first meridian, the longitude of every part 
of the continent of America will be west; but if Washington or any other city in the 
United States be fixed on, part of our territory will be in east and part in west: this 
would be troublesome and inconvenient, and might be productive of serious error. 
For these reasons the longitude of the following places has been reckoned from Green- 
wich, which I sincerely hope, will, in the construction of the map, be adopted as the first 
rneridian. 
For the determination of the latitudes of the places in the following table, the method 
above mentioned was generally adopted. Altitudes of the pole star (a Urse Minoris) 
were, however, measured when in any part of its circuit around the pole, and very many 
altitudes of southern stars were obtained, when at a short distance from the meridian to 
which they were reduced by the rules of spherical trigonometry. The altitudes of every 
star but the polar were reduced separately, and also of that when it was less than three 
hours from its upper or lower culmination, 
It will be seen that the observations for the determination of the latitudes of all the 
