174 Hij^ory of JJironomy for the Year iSoi. 



are further diftant than the earth : it is the 93d the orbits of 

 which are known. 



C. Lahinde junior has had the fatisfaftion of fiirniftiing 

 exaft poluions of ftars, before unknown, with which aflrono- 

 niers had often been obliged to compare thia comet j and the 

 fame thing has happened to him thele iiftecn years. 



The new tables of the moon by M. Burg form a very im- 

 portant epoch in the hiltory oi alh-onomy for this year. I 

 was informed by Dr. Von Zach that JNL Burg h^d been em- 

 ployed at Vienna, amidfl ])overtv and oljfcurity, in calculating 

 obfcrvations of the moon made at Greenwich, with the hope 

 of improving the tables of the moon : and on the 19th of 

 jNIarch 1798 the commiffioners of the Inftitute, being alTem- 

 blcd at the Board of Longitude to determine on the fubjedl 

 for a prize, I propofed to them to require the eltablillunent 

 of the epochs of the moon by a great luimbcr of obfervations. 

 1 knew- that M. Burg had calculated a great many, and I 

 ^udo^ed that this would cive him an opportunity of publifliing 

 \hem, and at the fame time afford us the means of rewarding 

 his labour. When the prize came 10 be adjudged, as C. Bou- 

 vard made a great many intercftmg refearches alfo, it was 

 thought proper lo divide it. But general Bonaparte, who 

 that ciav prefuled, propofed to double the prize, in order that 

 t-ach might have 54CO francs : and ibis was agreed to. 



C. Laplace, finding that this fum was too fmall for fo im- 

 menfe a labour as that of C. Burg, and that he could deduce 

 from thefe calculations all the moon's equations with a pre- 

 cifion never before obtained, induced the Board of longitude 

 to propofe a prize of 6ozo francs, and prevailed on the mi- 

 nifler (jf the marine and of the interior to furnifh each the 

 half of this fum. The queftion was publilhed on the 20th 

 of June 1800, and by the commencement of November 180a 

 we received the tables fo much wiflied for; and then feveral 

 fupplements. On the 26th of January C. Laplace announced 

 to the Intlitute, that he had found in the theory of the moon 

 an equation the period of which is 180 years, and which 

 amounts to 16''''; fo that it will ferve to explain the difagree- 

 ment obferved between the mean motion of the moon 100 

 vears a"0 and that given by the laft obfervations. This equa- 

 tion is compofcd of two terms, of which, for the moment, 

 we can have only the fum ; but it has t^rved to eftablifh in 

 the motion of the moon, at dlfTcrent periods, a regularity 

 uhich before could not be obtained. 



On the a^ihof July a deputation from the Board of Lon- 

 rltude went to give in its report to the firft conhil on the la- 

 bours of Burg, and the prize of 6000 francs. I reminded 

 6 hini^ 



