291 Astronomical Society. 



By applying this formula, however, to the eclipse in question, lie de- 

 duces certain results, which, in this case also, are subject to further 

 correction, depending on the true time of conjunction at Greenwich. 

 M. Mossotti likewise continued his observations on certain stars, with 

 which the Comet of Encke was compared on June 6, 1832, as recor- 

 ded in the same volume of the Memoirs, p. 245, for the purpose of 

 identifying the principal determining star used on that day. The 

 result of his observations confirms the accuracy of Mr. Henderson's 

 deduction, as recorded in p. 250. There is a remarkable circum- 

 stance, however, attending this inquiry, which is worthy of notice. 

 It appears, from p. 248, that M. Mossotti observed three stars, which 

 he compared with his determining star above mentioned, for the pur- 

 pose of identification when he should have an opportunity of seeing 

 the stars again ; they being at that time too near the sun. On his 

 reexamining this portion of the heavens at a subsequent period, he 

 was surprised to find that the second star was no longer visible. 

 He says that he looked for it several times, without success; and has 

 only been able to recognise the very small star, that was visible in 

 the field of view with the comet, as represented in the diagram. 



XL The following communication was received from Mr. Baily, 

 relative to the medal offered by His Majesty the King of Denmark for 

 cometary discoveries : 



" His Majesty the King of Denmark has been pleased to found a 

 gold medal, of the value of twenty ducats, to be given to the first 

 discoverer of a telescopic comet, subject to the following conditions, 

 which are, in some respects, different from those published in the 

 year 1 832. 



" 1 . The medal is to be given to the person who may first discover 

 a telescopic comei (that is, a comet not visible to the naked eye at 

 the time of its discovery), and not of known revolution. 



" 2. The discoverer, if in any part of Europe except Great Bri- 

 tain, must send immediate notice to Professor Schumacher, of Altona; 

 and if in Great Britain, or any other quarter of the globe except 

 Europe, must send immediate notice to Francis Baily, Esq., of Ta- 

 vistock Place, London. 



" 3. Such notice must be sent by the^rs^ post after the discovery, 

 and in case no post should be established in the place, then by the 

 ^r5< conveyance that presents itself, without waiting for more obser- 

 vations. A strict attention to this condition is absolutely necessary, 

 for, when it is not complied with, the medal will not be awarded at 

 all, if there be only one who has seen the comet; and, where it has 

 been seen by more than one, it will be given to the discoverer next 

 in order of time who does comply with this condition. 



" 4. The first notice should contain, not only the time of the dis- 

 covery, as nearly as the same can be ascertained, in order to avoid 

 any disputed claims, but also the best possible determination of the 

 position of the comet, and the direction of its course, if these points 

 can (even approximately) be ascertained from tlie observations of 

 one night. 



" 5. If the first night's observations are not sufficient to determine 



