384 On the Error discovered in tlie Nautical Almanac. 



cotangent, and log. tangent of right ascension instead of 

 log. sine of declination. 



As the right ascensions and declinations of the sun are 

 calculated from his true longitude, and apparent obliquity 

 of the ecliptic, we may derive these from the two equations 

 above, viz. 



R : 5,L : : s,0 : 5, declination, 

 Cot. L : R : : cos. O : tang, right ascension. 



Where L = the sun's true longitude, and O the apparent 

 obliquity of the ecliptic; but the method above shown is 

 much shorter in practice. 



With respect to that part of the statement contained in 

 the Philosophical Magazine, which accuses the French of 

 copying from the calculations of the Nautical Almanac in 

 making up the ephemeris for the Cmmoissance des Terns, — 

 it must be confessed that if they have declared that those 

 parts were actually calculated by then)selvcs, and not taken 

 from the Nautical Almanac, they are deservmg of censure; 

 but I must own, I never saw or heard anv one say that they 

 ever did see such a declaration : on the contrary, it is well 

 known, or at least was so to me and several other persons, 

 many years ago, that the French had of late years adopted 

 the calculations of the Nautical Almanac into their Cort- 

 naissance des Terns, by only allowing for the difference of 

 meridians. But no one would surely accuse them of im- 

 propriety for so doing : a mutual correspondence had always 

 subsisted between Dr. Maskelyne and the French astrono- 

 mers, and they may be said to have mutualiy contributed 

 their aid to the improvement of this great national work; 

 and for any one to convince themselves of this fact, they 

 need only read the preface to the Nautical Almanacs, where 

 Dr. Maskelyne says he has, at different times, received di- 

 rect communications not only from the French astronomers, 

 but from their Board of Longitude. In the preface to the 

 Nautical Almanac of 181 2, he expresses himself thus: " The 

 French Board of Longitude having been pleased to send me 

 a manuscript copy of new improved Lunar Tables by Mr. 

 Burg, of V^ienna," &c. : and again, " 1 be French Board of 

 Lonifitude having last year published M. De Lambre's new 

 tables of the sun, and iVlr. Burg's new tables of the moon, 

 and favoured me with copies for the use of the computers 

 of the Nautical Almanac, and myself, I have," &c. 



From which it clearly appears, that the French Buard of 

 Longitude did not send these copies merely in friendship 

 to Dr. Maskelyne, but for the use of the Nautical Almanac. 



They 



