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LXXVII. On Mr. Groombuidge's Tables of Vesta. 

 Bj/ W. M. MOSELEY, Esq. 



To the Editors of the Philosophical Magazine and Journal. 

 T AVAIL myself of your valuable publication, to express my 

 -* obligations to Mr. Groombridge for the satisfactory ex- 

 planation of the difficulty which I stated in your Magazme for 

 March, respecting the computed and observed places of Vesta 

 in July 1 822. Soon after I had transmitted the letter, it struck 

 me that some passages in it seemed to call too strongly upon 

 Mr. Groombridge to defend the assertion he had previously 

 made, regarding the orbit of the planet having been found less 

 than at first supposed ; but I beg leave to assure him, that 

 nothing was more distant from my thoughts at the moment, 

 tiian such a design. I fear, however, from the prompt and 

 explicit manner in which Mr. G. has answered the inquiry, in 

 your last Number, that he really did vieiso my communication 

 as directed to himself, — an impression I am very anxious to 

 effiice. 



The circumstance which Mr. Groombridge mentions in 

 regard to his method of applying only the equation of the 

 centre in forming his Ephemeris of Vesta, affords a reason for 

 the discordance which I had found between his positions and 

 mine. I used the whole panoply of Daussy's Tables, taking 

 out the small equations of longitude, where directed, to three 

 decimal figures. These minor equations sometimes amount 

 to upwards of 50', the omission of which must produce a con- 

 siderable difference in the final result. The planet, however, 

 may be found, in a telescope widi large field, by a less intri- 

 cate process. It was very unfortunate, that after preparino-, 

 with great trouble, many calculations of the place of this little 

 planet, during last summer, the weather was so perplexing 

 that I had not one opportunity of comparing the apjiarent 

 transit with the computed on those particular days which 

 were selected. How often have observers, in this climate, oc- 

 casion to regret the mortifying disappointments which occur 

 from our turbid atmosphere — " Dum latet obscura condita 

 niibc dies " ! Your obedient servant. 



May 9, 1823. W. M. MoSEIEY. 



LX XVIII. The Characters cf several rare and nndcscribed 

 Shells. Ihj Wm. Swainson, Esq. F.It.S. F.L.S. M. U.S. Sfc. 



'T'lIE number of shells, unrecorded by systematic writers, 

 -■- which exist in the cabinets of this country, is continually 



increasing. Every year witnesses the dispersion of collections, 



containing 



