Astronomical Society. 453 



the rate for a mean solar day. The author concludes his paper with 

 several practical examples of the method j and also with a formula 

 for reducing a series of observations made on any one night, to the 

 same altitude as shown by a series made on any other night : whereby 

 the whole become strictly comparable. 



Lastly, there was read the following communication from the Rev. 

 Thomas John Hussey, to Francis Baity, Esq. 



" In forming a correct catalogue of the stars situated between 15° N. 

 and 15° S. declination, and extending from 13 h 56 m to 15 h 4 m R.A. 

 from the catalogues of Piazzi and Bradley, and the observations of 

 Lalande and Bessel, Mr. Dawson and myself have been much struck 

 with the difference between the places of particular stars, as laid down 

 by Piazzi and Bradley, and the places assigned by reducing the ob- 

 servations of M. Bessel. The results obtained from the Histoire 

 Celeste come as nearly to the standard catalogue as can be expected, 

 considering the nature of the instrument employed for determining 

 the zenith distances, and thence the declination in which principally 

 the differences exist : some few of these between observations of the 

 same star are rather unaccountable, others may be attributed to 

 errors of the press ; they are as follow. — Histoire Celeste, 



Between the places shown by the observations of Lalande and those 

 of M. Bessel, even where there are more than one observation by 

 each of these astronomers, there are differences more or less consi- 

 derable in almost every instance ; occasionally, however, there is a sur- 

 prising coincidence. On this subject we may hereafter trouble you 

 with some remarks, my present object being to point out the differ- 

 ences between the standard catalogue of M. Piazzi and a catalogue 

 reduced to 1800 from the observations of M. Bessel, of the only stars 

 comprised within the above limits, which have been observed more 

 than once by M. Bessel, so as that the place of the star may be con- 

 sidered as pretty nearly ascertained by this indefatigable astronomer 

 alone. Their number amounts to 31, and the results are exhibited 

 in the following table. The differences are expressed in space. 



