which ivill happen on Septeinler 7, 1 820. 87 



account of the progress of the centre of this phaenomenon and of 

 its limits." M. De L'isle also, with a similar view, published a 

 notice to astronomers* in order, as he observes, " exciter les cu- 

 rienx de I'Europe, qui pourront voir I'eclipse anuulaire qui doit 

 arriver, d'y apporter toute I'attention possible, et de faire, de 

 bonne heure, toutes les dispositions nciicessaires pour la bien ob- 

 server ; afin de nous procurer tons les avantages que i'on en peut 

 retirer pour I'astronomie, la gtfographie, et la physique." 



It is worthy of remark that this eclipse (174S) was the first 

 that the celebrated Lalande (to whom the astronomical world is 

 so much indebted) ever saw. He was then only 16 years of age : 

 and the impression, which it made on him, fixed his future pur- 

 suits in life, and induced him to become an astronomer. It in- 

 deed excited so much attention in Europe that the King of France 

 (Louis XV) went purposely to Compiegne in order to observe it, 

 attended by the Abbe Nollet, and Messrs. De Thury and De La 

 Condamine ; and furnished with every convenient instrument for 

 the purpose. The royal astronomer there nia.de several impor- 

 tant observations f. M. Lemonnier likewise undertook the jour- 

 ney from Paris to Edinburgh, furnished with proper instruments, 

 purposely to observe it, during its annular appearance: and he af- 

 terwards published some important remarks thereon X- ^I- De 

 L'isle, abovementioned, published also a paper on the subject 

 entitled Nouvelle iheorie des eclipses, founded entirely on the 

 recent observations that had been made §. M. Pingre afterwards 

 added very considerably to these reflections in his interesting me- 

 moir, entitled Recherches sur la longitude des phisieurs villes\\, 

 Mechain likewise made a great many calculations relating to it, 

 from the manuscript collections of M. De L'isle. But it was re- 

 served 10 Lalande, /i/l!;/ years after the event, to deduce the most 

 •important conclusions from this singular phcenomenon, in his 

 paper Sur la grande eclipse annuluire de 174851. 



Considering therefore the interest which has always been at- 

 tached to this kind of phaenomeiia, and the important conclusions 

 to be drawn from them, I was somewhat surprised to find that 

 no particular notice has been taken of the ensuing eclipse either 



• AvcrtUscmcnt nux ustronomea snr I'Mlpsc unnnlaire du soldi que I'o/t 

 attend le 25 Juillft 1/48. It was published, however, only three months prior 

 to the eclipse taklnjj place ; so that there was scarcely time for it to get 

 into general circulation. 



f The name monarch had also made several observations on the eclipse 

 of I7''i7 at Versailles, attended by the celebrated Cassini. 



I See tlie Mhnoircs de I' Acad. Roy. des Sciences for 17'''''. pf^ge 4fi3. 



§ Ihid (or 1757, page 490. \\ Ibhlior 17*')(J, page I/- 



•I Sec Mhnoires de I'liutilut, {Scien. Math, ct I'/iy-) vol. ii. page 364- 



F4 in 



