392 Astronomical Society. 



fraction; and when the different jiortions belonging to the 

 different strata are put together in succession, they constitute 

 such an arrangement of quantities as proceed by a regular 

 gradation, or very nearly so; and nothing but a close exami- 

 nation of the difterences can detect that the whole succession 

 has not depended on one continued formula. Besides the at- 

 mospheric refractions adapted as corrections for celestial ob- 

 servations, the author has applied one of his formulae success- 

 fully to determine the terrestrial refraction as it has reference 

 to two objects standing in different elevations : so that whether 

 this memoir be considered as a meteorological, geodetical, or 

 astronomical communication, it cannot but be regarded as co- 

 pious, elaborate, and interesting. 



There vvas also laid before the meeting an account of ob- 

 servations made at Paramatta, in New South Wales, by Major- 

 Gen. Sir Thomas Brisbane, K.C.B. Governor, &c.; communi- 

 cated in a letter to Francis Baily, Esq. President of this So- 

 ciety. These refer to the solar eclipse on January 1, 182^; 

 to several occultations of fixed stars by the Moon ; to stars 

 observed with the Moon near her parallel ; to observations 

 before and after the superior conjunction of Venus with the 

 Sun, July and August 1824; to observations on the planet 

 Uranus near the opposition in July 1824; and to observations 

 on two comets, one of which was not observed in Europe. 



Next there was read a report On the properties and powers 

 of an altitude and azimuth circle constructed by Edward 

 Trouo-hton, and divided by T. Jones ; drawn up by the Rev. 

 W. Pearson, LL.D. F.R.S. and Treasurer to this Society. 

 The peculiarities of the construction of this fine instrument 

 cannot be adequately described in an abstract. But some 

 estimate may be observed of its accuracy from stating, that by 

 comparing the mean latitude of South Kibworth rectory (Lei- 

 cestershire) with each and all of sixteeii separate determina- 

 tions, it does not differ more than one second and one-tenth 

 from the extreme latitude ; that the true obliquity of the ecliptic 

 at the December solstice 1 824, as determined by this instru- 

 ment, was 23° 27' 44",01 ; whild the mean of the determinations 

 of Delambre, Brinkley, and Bessel is 23° 27' 44",55. Ob- 

 servations on the pole-star, and another determination of the 

 obliquity of the ecliptic, by a method suggested by Dr. Brink- 

 ley, serve still further to confirm the character of the instru- 

 ment for accuracy, and the value of such an instrument when 

 used by a skilful, scientific, and experienced observer. 



The reading was commenced of a paper On the construc- 

 tion and use of some new tables for determining the apparent 

 place of about 3000 principal fixed stars; drawn up, at the 

 request of the Council, by the President. 



nOYAL 



