4 



ScienUJic InteUigcncc,—3IccIianical Philosajjlif/. 1 CI 



the hair spring of gold, substances but little affected by tempevaiuje* 

 I — Rapport fait par Francaur. JBulh d'encour. JVov. 1829. 



10. Magnetic influence of }he solar beam; by P. Rilss and L. 



MosER.— Althougb some doubt had been entertained relative to the ' 

 accuracy of the conclusions of Morichini, which ascribed a magne- 

 tizing influence to the violet ray, yet the subsequent experiments of 

 ^ Mrs. Sommerville appeared to settle the question, and iocouCmn xho 



fact of such an influence. Resolved to subject tl)is question to new 

 trials, MM. Riess and Moser procured needles of .soft steel, of very 

 small magnitude, but having considerable surface, and they judged 

 of the acquired magnetism by the relative number of oscillations bc- 

 : fore and after the experiment. The spectrum \vhich they found was 



, always at a minimum of deviation, which corresponds with its great- 



; est intensity- The needles were upon a card, three or four feet 



from the prism, the chamber was darkened as slightly as possible, 

 and the lens had an aperture of 1.2 inches, and a focus of 2, 3 inches. 



The violet ray, concentrated by the lens, was passed in the several 

 experiments, from 100 to more than 500 times along one half of the 

 needle. In three instances tlie spectrum was kept stationary by 

 means of a heliostal, and the needle was exposed sev^enteen and a 

 half hours to the action of the ray. The experiments were also 

 varied agreeably to the method of Baumgartner, by using steel wire, 

 three inches in length, polished in different parts, and fixed vertical- 

 ly before and after each experiment. At the suggestion of M. Pog- 

 geadorff, they tried also the effect of polarized lights. 



It is sufficient to say, that the most careful attention to the results, 

 is altogether unfavorable to the opinion that the violet ray ])ossesses 

 any magnetic influence, and they conclude with observing, that there 

 is good reason for rejecting an opinion which, during seventeen years, 

 has from time to time troubled science. — Annalcs cle Chimle^ Xov. 

 1829. 



