Proceedings of the British Association. 269 



the principle on which corrections for aberration are applied in astro- 

 nomical calculations. 



< On the Aberration of Light/ by Mr. G. G. Stokes. — Mr. Stokes 

 supposes that the luminiferous ether is displaced by the motion of the 

 earth and planets through it, in a manner similar to that in which or- 

 dinary fluids are displaced by solids moving through them, though 

 not necessarily according to the same laws. He supposes that the 

 ether close to the surface of the earth is at rest relatively to that 

 surface, being entangled in the earth's atmosphere. Consequently 

 experiments on reflexion, refraction, and interference, made with the 

 light coming from any particular star, will lead to the same result, at 

 whatever time of year they are made, conformably with experiment. 

 He supposes that light is propagated through the ether in motion, in 

 the same way that sound is propagated through air in motion ; that 

 is to say, he supposes that the displacement of a small portion of a 

 wave's front in a very short time is compounded of the displacement 

 which would exist if the ether were at rest, and of the displacement 

 of the ether itself, so that in general the direction of a normal to that 

 portion of the wave's front is changed by the motion of the ether. 



' On the Elementary Laws of Statical Electricity,' by W. Thomson, 

 B.A. — Of late years some eminent experimentalists, and especially 

 Mr. Snow Harris and Mr. Faraday, have begun to doubt, to a certain 

 extent, the truth of Coulomb's laws, and have entered upon the inves- 

 tigation of various phenomena which appeared to be incompatible 

 with them. The principal subject of this paper was an attempt to 

 show that almost all the results adduced in their memoirs, which refer 

 to electricity in equilibrium, are necessary consequences of the ma- 

 thematical theory, and that none are at variance with it. 



'On the Nebula 25 Herschel, or 61 of Messier' s Catalogue,' by 

 the Earl of Rosse. — Lord Rosse exhibited to the Section what he 

 called his working plan of this nebula, and explained his method. 

 He first laid down, by an accurate scale, the great features of the 

 nebula as seen in his smallest telescope, which, being mounted 

 equatorially, enabled him to take accurate measurements ; he then 

 filled in the other parts, which could not be distinguished in that 

 telescope, by the aid of the great telescope ; but as the equatorial 

 mounting of this latter was not yet complete, he could not lay these 



