Hlftory of AJironovvy for the Year i8oO. ^ 



i«/b of twenty large charts. They may be had at the CoU 

 lege de France, at Paris. 



The conckifion of the ceatury has been diftinguiftied 

 alfo in a very remarkable manner by the theory of the moon. 

 On the 13th of Jyne Laplace announced a new refult of the 

 theory, which is a nutation of the lunar orbit, refulting from 

 the oblate figure of the earth. According to this inequality, 

 we may fuppofe that the lunar orbit, inftcad of moving with 

 a conftant inclination to the ecliptic, moves in a plane paffing 

 through the equinoxes between the equator and the ecliptic, 

 inclined to the latter at an angle of fix or feven fcconds. He 

 has found ,$jfo an inequality of the moon, depending on the 

 longitude of the node, which is fix feconds. Difputes were 

 Jong maintained refpe6ling this inequality, which the Engl i{h 

 totally ncgleded, and which did not feem to be indicated by 

 theory. 



The motion of the moon during the courfe of 1002 years was 

 attended with a difficulty which has been now removed. The 

 obfervations of the Arabs in the tenth century were of great 

 importance in this refpe(9:. We were acquainted only with 

 three, when I difcovered among the manufcripts of my old 

 mailer, Jofeph Deliflc, an Arabic copy of a part of the work 

 of Ibn lunis, which contained a great many; but the ori- 

 ginal was at Leyden ; and we long folicited the Batavian go^ 

 vernrnent to entrud us with it. At length, on the 26th of 

 May 1799, the ambaflador brought to the Inftitute this va- 

 luable manufcript, written in a fmall chara(!-^er, and forming 

 400 pages in quarto. Cauffin is employed in giving a com- 

 plete tranfiation of it; and we hope, that not only the tranf- 

 lation, but alfo the Arabic original, as far as it relates to the 

 obfervations, will be printed at Paris. Caufl[in has already 

 tranflated that which I procured him. He was aflTifted by 

 Bouvard in regard to the aftronomical part and the calcula- 

 tions. The refuks of the obfervations of the moon have been 

 already printed. 



The Inilitute had propofed as the fubje6l of a piize, the^ 



comparifon of a great number of obfervations of the moon, 



ivith the tables to fix the epochs of the longitude of ihc moon^ 



8 of 



