176 French National Injlltuie. — -Tcrrejlrial RefraBton. 



The planet which we announced in the account of the la- 

 bours of the laft quarter, difcovcrcd by Dr. Others, of Bre- 

 men, has alfo engaged the attention of all aftronomers. 



It was obferved by C. Mechain till the 28th of Auguft, 

 and a fufficient number of its pofitions was obtained to de- 

 termine the elements of its orbit in fuch a manner as to en- 

 able us to find it again fome months hence, when it will ap- 

 pear in the morning after ilTuing from the ravs of the fun. 

 C. Burckhardt, adjund of the board of lonoitude, prefenled 

 fome to the clafs, which he calculated, taking into account 

 even the perturbations which this planet experiences from 

 the principal part of the reft. Thefc elements reprefent very 

 well all the obfervations hitherto made. C. Vidal, diretlor 

 of the obfervatory of Touloufe, placed under a llcy fo favour- 

 able to aftronomy, followed the planet of Olbers with the 

 fame attention and conftancy which he employed in the ob- 

 fervations of Mercury, which are fo difficult; and he fent to 

 the clafs forty, with a table containing twenty-three ftleft 

 determinations of its right afcenfion and dccllnalion, and a 

 chart of its apparent route from the 19th of May to the 23d 

 ofAuguft. 



In this period of time it paffed over about 17 degrees in 

 right afcenfion and 5 in declination. 



It .appeared to C. Vidal as a ftar of the ninth magnitude, 

 and exhibited no trace of that nebulofity with which comets 

 are always accompanied. 



NATURAL PHILOSOPHY. 



Ohfervatton of a remarkable Vhanomenon of Tcrrejlrial Rt:- 

 fraSion. 



The mod remarkable of the phyfical pha>,nomcna next to 

 thofe which iiifpire moft men with tciror, are thofe Angular 

 appearances which are produced fometimes by the refledlion 

 or refraftion of parts of the atmofphere, and towards which 

 the attention of philofophers has been dire6led by the ob- 

 fervations of C. Monge. 



This circnmftance reminded C. Dangos of an effcft of ler- 

 reftrial refraftion which he witncllcd at"Malta in 1784. 



On the 33ih of March, about one in the afternoon, he 

 learned, by loud (bouts, which rcfounded from all the ftreets 

 of the town, that a new ifland had arifen in the channel of 

 Malta, Having afcended to one of the terraces of the ob- 

 fervatory, he indeed obferved a very white tra6l of land in 

 the middle of the water, the form of which wag nearly that 

 of a right cone irregularly truncated. The ih ^ r 



eomplele, that fome of the failors had rL-folved " ^^^ 



'° go and re- 



