516 Prof. G. B. Airy on the History of the Discovery of 



subsequently printed in the Memoirs of this Society. The 

 progress of the errors of the tables of Uranus was here clearly 

 marked. 



'In 1837, 1 received from M. Eugene Bouvard a letter, from 

 which I trust I may be permitted to make an extract. It will, 



I am certain, be received as creditable to the intelligence and 

 industry of the astronomers of the Observatory of Paris. 



No. 3. M. Eugene Bouvard to G. B. Airy. 

 [extract.] 



" Paris, ce 6 Octobre, 1837- 

 "Dans le peu de moments de loisir que me laissent mes 

 fonctions, je m'occupe d'un travail que je crois n'etre pas sans 

 importance. Mon oncle [M. Alexis Bouvard] travaille a re- 

 faire ses tables de Jupiter et de Saturne, en se servant des 

 corrections apportees recemment aux elemens astronomiques. 



II m'a cede les tables d' Uranus a reconstruire. En consultant 

 les comparaisons que vous avez fait des observations de cette 

 planete avec les calculs des tables, on voit que les differences 

 en latitude sont tres-grandes et qu'elles vont toujours en aug- 

 mentant. Cela tient-il a une perturbation inconnue apportee 

 dans les mouvemens de cet astre par un corps situe au-dela ? 

 Je ne sais, mais c'est du moins l'idee de mon oncle. Je re- 

 garde la solution de cette question comme fort importante. 

 Mais, pour reussir, j'ai besoin de reduire les observations 

 avec la plus grande precision, et souvent les moyens me raan- 

 quent." 



The remainder of this letter relates principally to the re- 

 duction of observations. 



The following are extracts from my answer : — 



No. 4. G. B. Airy to M. Eugene Bouvard. 

 [extract.] 

 "Royal Observatory, Greenwich, 1837, Oct. 12. 

 " I think that, probably, you would gain much in the accu- 

 racy of the reduced observations by waiting a short time be- 

 fore you proceed with that part of your labour. Some time 

 ago, I presented to the Astronomical Society of London a 

 very complete reduction of the observations of all the planets 

 made at Cambridge in the years 1833, 1834, 1835. This 

 paper will, as I expect, very shortly be printed. I have re- 

 duced the observations made at Greenwich in 1836 in the 

 same manner : the volume containing these reductions will 

 very soon be published. * * * You may also know that 



