520 REPOET — 1889. 



electrical energy at command to render the result clearly apparent, I waited until 

 an opportunity occurred. 



A friend placed at my disposal a battery of sufficient power, and plates of great 

 sensitiveness, with the following- results : — • 



By placing photographic plates between the poles of a powerful electro-magnet 

 and intermitting the current, an action similar to that of light is produced, which 

 on development shows a nebulous appearance in the part directly between the poles 

 and an intense spot at some distance from them. 



The magnet used was formed of a ring of soft iron with two solenoids within 

 the diameter ; the poles of the solenoids were within fifteen millimetres of each 

 other. The plates first used are known as ' Lumiere.' 



12. Physical and Chemical Constitution of Comets and Meteorites. 

 By Philip Bkaham, F.C.S. 



The interest which attaches to these periodic and spasmodic visitors, the specula- 

 tions concerning their place in cosmogony, and their constitution physically and 

 chemically, are questions to which I ofl'er these possible solutions. 



In accordance with recorded investigations comets are extremely attenuated 

 masses of gas with very little solid matter. 



Meteorites are solid masses of matter with very little gas. 



The evidence of the presence of carbon and hydrogen has been invariably found 

 in the spectra of comets. 



In meteorites which have fallen the usual meteoric metals have been found, but 

 the occluded gases vary, and might be acquired during their passage through the 

 earth's atmosphere or after their lall. 



I venture to intimate that the result of the formation of a solar system is 

 an ellipsoid of magnetic force, the major diameter being in the mean plane of the 

 system with the poles at the extremities of the minor. 



The angle at which the plane of the orbit of the comet, and the velocity with 

 which it cuts through this ellipsoid, determines the brilliancy, and the resulting 

 electrical excitements account for the different appearances of these bodies. 



Q'he brilliancy of meteorites is due to the heat produced by friction during their 

 passage through the earth's atmosphere. 



I have every reason to believe that the gaseous constituents of a comet are 

 aqueous vapour, carbonic acid, and nitrogen in variable proportions. 



The above conditions, I conclude, may be the physical and chemical means 

 whereby these phenomena are produced. 



13. Report of the Committee on certain proposals relative to the Unification 

 of Time and the adoption of a Universal Prime Meridian. — See Reports, 

 p. 49. 



