187 
PHYSICAL AND MATHEMATICAL SECTION. 
April 26 th, 1866. 
E. W. Binney, F.R.S., F.G.S., President of the Section, in 
the Chair. 
A paper entitled “ Results of a Comparison of the Magni- 
tudes of the Bedford Catalogue with those of the Mensurse 
Micrometricse and the Bonner Sternverzeichniss,” by George 
Knott, Esq., F.R.A.S., was communicated by Mr. Baxen- 
dell. 
The question of the relation between the magnitude scales 
of different observers is one of considerable interest and im- 
portance, and has engaged the attention of several able 
astronomers. It is not my intention in this paper to go into 
the subject generally, but simply to submit the results of a 
comparison of the magnitudes of the late Admiral Smyth’s 
Bedford Catalogue with those assigned to the same stars by 
the late Prof. Struve in the Mensurce Micrometricce , and by 
Dr. Argelander in the Bonner Sternverzeichniss, I may 
remark that I was induced to undertake the comparison by 
the perusal of an interesting paper by Mr. Pogson, the pre- 
sent Director of the Royal Observatory at Madras, in vol. xvii. 
of the Monthly Notices of the Royal Astronomical Society, 
in which he has given a short table of corresponding magni- 
tudes of Struve, Bond, Herschel, and Smyth, as referred to 
Peoceedin g-s — Lit. & Phil. Society. — Vol. V. — No. 16— Session 1865-6. 
