38 Hijiory of Afronomj for the Year 1799. 



perturbations of Mars by the aftion of Jupiter and the Earth, 

 which Schubert and Oriani had before calculated, nnd with- 

 out which we could not have hoped to^ carry our tables to 

 the fame degree of perfeftion. 



The collection of obfervations made at Greenwich by the 

 celebrated Bradley and his afliftants between 1750 and 176:2 

 has appeared in England, but I have not yet been able to 

 procure it. 



Mifs rierfchel has publiflTcd a volume on the flars, not of 

 obfervations, but refearches refpcAing the grand Britiflv ca- 

 talogue of Flamftead, and the obfervations of that celebrated 

 aflronomer; where flie has found 500 ftars which are not 

 151 the catalogue, as flie has found many in the catalogue 

 which are not in ».he obfervations. 



C. Kramp, Profeflfor at Cologne, has publiflied an analyfis 

 of aftronomical refraftions, in which he has been able to 

 determine the refraftion accuratclv and algebraicaliy with-r 

 out employing any hypothefis or approximation. This work 

 leads us one fi-ep farther in this difficult part of aitronomy. 

 It was proclaimed, with the other important works of the 

 year 7, at the laft exhibition at the Mufcum. 



The Academy of Stc^kholm has fent M. Swanberg to 

 I^pland to iind out the llations which ferved in 1736 for 

 meafuring a degree under the polar circle. He employed 

 Iiiinfelf only in difcovering their local fituation ; but he fays 

 lie found two minutes error in the reduction of the ftations 

 to the horizon, which might have arifen from fomc defeft 

 in the indruments, or from teneRrial rcfraclion. I have 

 been informed in a letter from Sweden, that Maupertuis 

 propofed to recommence the meafurement at his own ex- 

 pence. This proves that he was not entirely fatisfied with 

 the refult, which differs confidcrably from niany other de- 

 grees that have been mealured. The local inequalities of 

 the ground, however, may have been the caufe of this di- 

 verfity. 



C. Defortia, as well (killed in Greek as in Geometrv, has 

 made a new tranflalion, with learned notes, of the book of 

 Ariftarchus of Samos, refpefting the diltance of the fun and 

 tlie moon, collated with ten other manufcripts. This cele-- 



bratcd 



