Prof. Lovering on the American Prime Meridian. 189 
Let us next consider the chief aim contemplated in the estab- 
lishment of a Nautical Almanac. ‘here can be uo doubt that 
the British Nautical Almanac, at least, was designed for the benefit 
of seamen exclusively. Before its foundation in 1767, each navi- 
gator calculated the places of those bodies which he used in his 
reckoning for longitude directly from the tables. Thus he was 
liable to an error of a degree or about sixty geographical miles, 
in assigning his position at sea. Then it was proposed that the 
places of the moon and other useful bodies should be calculated 
from the tables by able astronomers: that these places, corres- 
ponding to short intervals during the day, should be published ; 
tested in manifold ways by expert computers, must vastly trans- 
cend in accuracy the best that could be made by the most skilful 
sailor amid the other duties, vexations and perils incident to his 
profession. Such I believe to have been the design of Nautical 
Almanacs, whenever and wherever they have been instituted. 
he same considerations dictate that no innovations, such as 
the change of an established prime meridian, whereby fresh per- 
Plexities and dangers may be entailed on a profession already too 
much exposed to uncertainty in every form, should be made with- 
Out the most clear exhibition of their necessity. I do not sup- 
pose that an American sea-captain, qualified to navigate a ship 
across the Atlantic, is incapable of understanding the relations of 
different meridians, and of allowing, whenever he compares his 
reckoning with that kept on board a British vessel, for any differ- 
€nce which may hereafter exist in the established prime meri 
lans of Great Britain and the United States. I only say that this 
labor, which might generally be done with accuracy, would occa- 
Sionally lead to mistakes and ought not to be required of the 
havigator, unless there is some uncontrollable necessity for it. 
Otherwise, the very class of men for whose benefit an American 
Nautical Almanac should be designed, will be the most injured by 
it. I object, therefore, to any change in the prime meridian to 
Sources and their science, have estab a prime meridian in 
