Discovery of an Error in the Nautical Almanac. 63 



phical Magazine appeared in public ; which was as fol- 

 lows : 



" Dear Sir, — T think every person whose curiosity has 

 been excited bv tlie supposed error in the Nautical Alrnanac, 

 must feel much indebted to you for your communication on 

 the subject, which I accidentally met with yesterday in Til- 

 loch's Journal. Your statement is, I hive no doubt, per- 

 fectly correct, and has, indeed, anticipated the very little I 

 had intended to say, in a note, whenever a new editu.'n of 

 the Almanac shall be called for. I never, willimjly, conid 

 adopt the supposition that the supposed error ever proceeded 

 from any thing like inaccuracy or inattention, and yt ur 

 explanation has removed the very little doubt I ever Lad 

 upon the subject. 



'* I remain, dear sir, 



" Very faithfully yours, 



«' Roj-al Observatory, Dec. 6, 181 1. «< J. PoND." 



I shall conclude, that Dr. Kelly's letter, amongst a vast 

 variety of false conjecture and mistatement, is calculated 

 to (\o considerable injury to the credit of the Nautical Al- 

 manac ; but I hope a new edition of that work will not be 

 published till the whole of the former edition is sold off; 

 nay, I think it would be a reflection on the ability and indefa- 

 tioable care of Dr. Maskelyne to do it, perhaps scarcely al- 

 lowable to make any alteration in a new edition, unless the 

 facts were established upon which such an alteration could 

 fairly he adopted *. 



I therefore trust Mr. Pond will, before he adopts such a 

 measure, fully weigh the circumstances under which our 

 present knowledge of the quantity of the obliquity of the 

 ecliptic has been'derived ; that he will not set aside the work 

 of so great an astronomer as Dr. Maskelyne, without the 

 best grounds founded on ot)servation to justify his mea- 

 sure; and that he will not suffer the discrepancy between 



• I have met with persons who have deferred the purchase of the Nautical 

 AtmauHC for 1812, under the expectation of the publication of a mw edition, 

 which, they were led to believe from the account in the Philosophical Ma- 

 gazine, would soon make its appearance, and no doubt but many more have 

 been influenced by the same expectation. But the circulation of t'lis sup- 

 posed error in the public Newspapers must necessarily tend to render that 

 class of people to whom the use of the Nautical Almanac is the most im- 

 portant, dissatisfied, producing a doubt on tlieir minds of the accuracy of the 

 calculations composing that work J for the sai'or knows not, nor cares I'.o:, 

 about the obliquity of the ecliptic; he works by precise rules, which, if they 

 give him his sit'j:.tion, is all he wants. I'he principles by which it is obfiined 

 are immaterial, he wants only faith in the iniiniiiieiit by which it is obtained, 



the 



