301 
Frsrvary 1itu, 1856. 
SIR ROBERT KANE, Vice-Presipent, 
in the Chair. 
SamuEL Downrine, Esea., and James West, Esq., High 
Sheriff of the City of Dublin, were elected Members of the 
Academy. 
Mr. Hennessy described an optical phenomenon which he 
observed on the 3rd of last July in the Atlantic, while on a 
voyage to Havre. It was a coloured glory, such as has been 
already minutely described by other observers, especially 
Scoresby and Saussure, but this instance was particularly re- 
markable from the conditions that accompanied it, and which 
pointed in a decisive manner to the true theoretical explana- 
tion of such phenomena. The day when this glory was ob- 
served was remarkably sultry, and the sea, which was perfectly 
smooth, was covered with scattered patches of fog. At 4} 
p.M. Mr. Hennessy’s attention was directed to a bank of fog 
close to the vessel, and in the direction exactly opposite to the 
sun. Three rings, sensibly concentric, were distinctly visible 
in the fog bank: the first or outermost was nearly pure white ; 
the second presented faint traces of prismatic colours; and the 
third, which had a diameter considerably less than the others, 
showed a series of brilliant colours, namely, violet, red, yellow, 
green, and blue. As usual, the centre of this ring contained 
a very distinct shadow of the observer’s head. The produc- 
tion of these rings could not be ascribed as the influence of 
minute icy crystals floating in the fog, as has been frequently 
supposed, but must be attributed to the optical action of the 
vesicles of vapour, for the temperature of the air over the sea, 
upon which the fog bank rested, was that of a warm summer 
afternoon, and very considerably above the freezing point. 
