426 
tation. And further, that the Member of each Committee to 
retire from the Council be that one who has given the least 
number of attendances during the year.” 
The amendment having been negatived, the original Re- 
commendations of the Council were put and carried. 
In the absence of the author, the Rev. T. R. Robinson, 
D. D., Sir Robert Kane read a second notice on the Luminous 
Phenomena produced by the discharge of Ruhmkorff’s In- 
duction Apparatus in vacuo :— 
«‘In the Proceedings of the Academy, January, 1856, I 
have given an account of some observations respecting the 
appearances produced by the discharge of induction currents 
through an exhausted receiver; especially the division of the 
luminous stream into a number of spherical shells, whose 
centre is the point from which the positive discharge issues, 
and the influence which the presence of gaseous or vaporous 
matter has on the production of those rays which have the 
power of exciting fluorescence. Since that time I have pur- 
sued the subject at such few moments of leisure as I could 
find ; and I hope the facts which I have observed may not be 
unworthy of the Academy’s notice. If it seem that I detail 
them too minutely, it must be remembered, that.as long as we 
are ignorant of the cause of a’ phenomenon, it is impossible to 
decide as to the importance and significance of any of its 
features. 
‘“‘Nothing satisfactory has yet been ascertained as to the 
cause of the stratification of the light. Mr. Grove, ma com- 
munication to the British Association at Cheltenham (which 
I know only from a very brief notice in the ‘ Atheneum’), 
appears to think that it arises from some vibration in the 
metal of the contact-breaker, which produces a fluctuation in 
the inducing current. He finds that it is not always visible 
in the light caused by a single discharge, and that itis influ- 
