Mrs, M. SoMERViLLE on the magnetizing power, &c, 133 



netised, and run through a small piece of cork, into which a 

 conical cap of glass is inserted ; the whole traverses on the 

 point of a needle fixed perpendicularly in a stand. 



I had no information at this time of the manner in which 

 Professor Morichini had conducted his experiments ; but it 

 occurred to me that it was not likely that if the whole of the 

 needle were equally exposed to the violet rays, the same 

 influence should, at the same time, produce a south pole at 

 one end of it, and a north pole at the other. I therefore 

 covered half of the needle with paper, and fixed it to the 

 panel with wax, between ten and eleven in the morning, in 

 such a position that the uncovered part of it should be exposed 

 to the violet rays. The needle was placed in a vertical plane, 

 nearly perpendicular to the magnetic meridian, and inclined 

 to the horizon. As I had not a heliostat, it was neces- 

 sary to move the needle in a direction parallel to itself, to 

 keep the exposed portion of it constantly in the violet ray. 



The sun was bright at the time, and in less than two hours 

 I had the gratification to find that the end of the needle 

 which had been exposed to the violet rays attracted the 

 south pole of the magnetic needle, and repelled the north 

 pole. It had been previously ascertained that there was no 

 iron near to disturb the results. The experiment was also 

 repeated on the same day, under precisely similar circum- 

 stances, with the view of detecting any source of error that 

 might have escaped observation in a first attempt ; but the 

 result was the same as in the first. 



The season was so favourable that it afforded me daily 

 opportunity of repeating the experiments, varying the size 

 of the needles, always taking especial care to ascertain that 



