226 Proceedings of Philosophieal Societies, [Mjincrf, 



on the chemical rays, magnetism was imparted to steel in a shortet 

 time than by that ray in its ordinary state. 



It was found to be unnecessary to darken the room for these 

 experiments, it being sufficient to throw the spectrum on a part 

 of the room where the sun's rays did not shine. 



Mrs. Somerville next tried the effect of the solar rays as 

 transmitted by blue glass ; and on needles being exposed, half 

 covered as before, under glass coloured blue by cobalt, care 

 being taken that no magnetic substance was present, they also 

 were magnetized. It was not ascertained whether the rays 

 ■which produce chemical charges had any share in this effect^ 

 for by subjecting two slips of paper, dipped in solution of mu- 

 riate of silver, to the action of the sun's rays under the blue and 

 under common white glass, both were blackened in the same 

 time and to the same degree. Needles exposed in the same 

 manner under green glass were also magnetized. 



By inclosing needles in pieces of green and blue riband, half 

 of each being covered with paper, and hanging them up in the 

 sun for a day, behind a window-pane, they likewise acquired 

 polarity ; the exposed ends becoming north-poles as usual. But 

 no effect was produced, by the same treatment, on needles 

 inclosed in red, orange, or yellow silk. 



Throughout the experiments detailed in this paper, with a 

 very few exceptions, seemingly attributable to a predispositioti 

 to magnetism too slight to be detected, the exposed end of thfe 

 needle, &c. employed, became the north-pole. From ten to 

 twelve and one o'clock appeared to be the most favourable time 

 for the experiments. As the season advanced, the magnetism 

 acquired was less permanent, or the needle required expo- 

 sure for a longer period to render it permanent, and the effect in 

 general decreased. The author infers from the whole, that the 

 more refrangible rays of light have the property of imparting 

 magnetism. 



The reading was also commenced of a paper. On the Action 

 of Sulphuric Acid upon Naphthaline; by M. Faraday, Esq. FRS. 



Feb. 9. — James Holman, Esq. was admitted a Fellow of the 

 Society; and the reading of Mr. Faraday's paper was continued. 



Feb. 16.— Charles Lyell, Esq. FL. and GS. and Dr. J. A. Ogle 

 were respectively admitted Fellows of the Society, the name of 

 John Hawkins, Esq. ordered to be inserted in its printed lists; 

 and the reading of Mr. Faraday's paper was concluded. 



In consequence of the peculiar action of sulphuric acid upon 

 certain hydrocarbons, observed by the author, and referred to in 

 a late paper on New Compounds of Carbon and Hydrogen,* he 

 was led to examine the effect produced by treating various sub- 

 stances with sulphuric acid, and amongst others, naphthahne. 

 It was soon found that a new compound was produced, very 

 peculiar in its composition and properties, the existence of 

 * See Amah for January, p. 48. 



