/ 



172 Scientific Intelligence. — Mechanical Philosophj. 



he found that hi the course of five minutes, the whe when presented 

 to a magnetic needle, manifested very decidedly the existence of 



poles. 



The violet ray changed or reversed a well marked pole in a soft 



iron needle. 



The red, yellow, orange and green ray produced no alteration 

 whatever in a magnetic needle, nor in one which had no sensible 

 magnetism. 



A soft Iron wire, covered with a coat of oxide, and strongly mag- 

 netized, exposed to the violet light, in three minutes, had its south pole 

 transformed to a north pole. 



A soft w^ire, magnetized, being bent, and both ends exposed to the 



violet ray, in ten minutes, both ends became north. 



If the wire was oxidized, tliis change was effected In five minutes. 



These experiments were so often repeated as to leave no doubt of 

 the magnetizing pjoperty of the violet ray. 



In the course of his investigations, Prof. Z. ascertained that Iron 

 obtained from a sulphurous mine, could not be thus magnetized, 

 nor was it easy to produce much effect upon iron highly tempered. 



At low temperatures, also, such as 6^ R. 0, + 10^, the results are 

 very equivocal. But at + 20^, Centig. the temperature of Mrs. 

 Somerville, or at 25^ or 26'=',R. that of Prof. Z. the resuks are very 

 striking. 



If the middle of the needle be placed in the violet ray, the effects 

 are weak or uncertain. 



Perceiving that the carburets* could acquire magnetism and not the 

 sulphurets* — that needles artificially oxidized, presented die phenom- 

 enon in question more promptly than those which are not so, and that 

 the effect increases or diminishes with the temperature. Prof Z- is 

 confirmed in the opinion that the action of the violet ray is chemical. 

 The light of a candle gave him, in three fourths of an hour, a slight 

 degree of magnetism, but the violet llglu of the moon had no effect- 

 The latter was tried, however, at a temperature not exceeding 5*^, R* 



Prof. Z- finds his needles retaining their magnetism, at the end oi 

 eight months. — Bib. Univ. Mai, 1S2D. 



♦ Ofhuii.— £J 



