146 Proceedings, of Philosophical Societies. [Ffiti. 



mas, a«d Mr. Diinlop, on the inferior Conjunction of Venus with 

 the Sun, in October, 1823. 



Sir Thomas's second communication, which is dated 17th 

 April, 1824, contains, first, a record of repetitions on the Sun, 

 with Reichenbach's circle, for the Summer Solstice, 1823, they 

 extend from Dec. 10, 1823, to Jan. 2, 1824, but have not yet 

 been subjected to the necessary reductions for a definite result : 

 secondly, a series of observations on several stars, made at Para- 

 matta with the Mural circle, from Nov. 20, 1823, to Feb. 19, 

 1824. Twenty of the stars observed are among those whose 

 places are given annually in the Nautical Almanac, and are 

 usually denominated Greenwich stars. 



A letter was also read from Baron Zach to Francis Baily, Esq. 

 FRS. dated Genoa, July 21, 1824, announcing the discovery of 

 a telescopic comet, by M. Pons, on the 24th of that month. It 

 was in the head of Serpentarius, without tail or coma : — a sivuple 

 nebulosity. 



Mr. Herschel submitted to the inspection of the members 

 present, a new double image micrometer, by Prof. Amici, of 

 Modena. 



Mr. Donkin laid on the table, for the inspection of the mem- 

 bers, an instrument made by M. Fatten (a pupil of Breguet, at 

 Paris), for determining the fractional p ait of a second of time, 

 in astronomical observations. 



Prize Questions proposed by the Astronomical Society of London. 



This Society has just proposed the following prize questions^ 

 to the consideration of astronomers and mathematicians, viz. 



1. The silver medal to any person who shall contrive, and 

 have executed an instrument, by which the relative magnitude 

 of the stars may be measured or determined ; and of which the 

 utility for this object shall be sufficiently established, by nume- 

 rous observations, and comparisons of known stars. 



2. The gold medal for approved formulae, for determining the 

 true place of either of the four newly discovered planets, Ceres, 

 Juno, Vesta, and Pallas ; within such limits as the Council may 

 think sufficiently correct for the present state of astronomy ; 

 such formulse in each case to be accompanied with comparisons 

 of the observed places at various periods. 



3. The gold medal for a new mode of developing the differen- 

 tial equation for expressing the problem of the three bodies, by 

 which a smaller number of tables shall be required in order to 

 compute the moon's place to the same degree of accuracy, as by 

 any existing tables, and with greater facility. ' 



To be entitled to competition for the prizes, all answers to the 

 first question must be received before the 1st of February, 1826; 

 to the second, before the 1st of February, 1827; and to the 

 third, before the 1st of February, 1828. 



