0/2 the Annular Eclipse of the Sun, Sept. 7, 1 820. 85 



gratification is the reflection of having been a zealous promoter 

 of mathematical science for upwards of sixty years, as a teacher, 

 fhiefly at the Uoyal Military Academy at Woolwich ; as a labo- 

 rious contributor to the Philosophical Transactions, and an Edi- 

 tor of that work; as the conductor of certain scientific .louvnah 

 which have met with great encouragement ; and also as the au- 

 thor of several successful pubHcations on mathematical subjects. 



'^ If I feel this satisfaction in a retrospect of laborious appli- 

 cation in the zealous pursuit of those elementary sciences, which 

 lead to the knowledge of the Principia and other works of cur 

 immortal Newton ; how much more gratifying must your reflec- 

 tions be, in having so ably illustrated as well as honoured our 

 great author, and carried his discoveries higher than perhaps he 

 himself could have ever contemplated ! 



'' That you may long enjoy this gratification, and continue to 

 enlarge the boundaries of science, is the sincere wish of 



*' Your most obedient and faithful servant, 



" Chaui-Ios IlnrroN." 

 To the Marquis de Laplace, 



XII. Memoir relative to the Annular Eclipse of ike Sun, which 

 will happen on Sepiemler 7, 1820. JBy Francis Baij.y. 



X HE solar eclipse which will happen on Thursdav, September 7» 

 1820, will be the greatest of all those which have happened in 

 this part of Europe ever since the year 17(t4 ; and indeed of ail 

 those which will again happen here before the year 1847. Like 

 the two eclipses above alluded to, it will be annular: that is, the 

 disc of the moon will not wholly cover the disc of the sun ; but, 

 in certain parts of the earth, the sun will show the appearance 

 of an annulus, or ring, round the body of the moon ; the posi- 

 tion and magnitude of which will depend on the situation of the 

 spectator. In no part of England, however, will this annular ap- 

 pearance be observed * : but, on the continent, in any part of 

 that tract of country which extends nearly in a straight line from 



the north of Westphalia to the south of Italy, the inhabitants will 

 have an opportunity of beholding this singular phnsnomenon. 

 Annular eclipses do not appear to have been noticed by the 



L.icients, who probably confounded them with partial ones. In- 

 deed, the only authentic accounts of any well observed annular 

 eclipses in this part of Europe (besides the one in 17(54 above 



mentioned) are those of February IS, 173G-7 and of July H, 



' The eclipse however will be annular in the Shetland islands: and it will 

 be of con&idcruble magnitude along the whole eastern coast ol'tJrtat Britain. 



F3 17 JS; 



