522 ©. Scientifie Proccedings, Royal Dublin Society. 
case of buoys where the lamp, owing to the motion of the sea, is 
-unsteady, the flashes, for all practical purposes, are sufficiently 
regular and distinctive. 
Norz.—The Paper was illustrated by a working model showing 
‘the movement to which buoys are subjected by the action of the sea, 
‘and the gimbal arrangement by which that motion is neutralised 
and the flame of the lamp kept steady, an occulting apparatus 
‘(showing white and red light alternately) being fixed in connexion 
with the gimbal arrangement. ' 
