Scientific Intelligence. — Mechanical FJiilosophy. 1 8 1 



the hair spring of gold, substances but little affected by temperature. 

 — Rapport fait par Francceur. Bull, d'encour. JYov. 1829. 



10. Magnetic influence of the solar beam; by P. Riess and L. 

 MosER. — Although 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 to confirm the 

 fact of such an influence. Resolved to subject this 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 be- 

 fore and after the experiment. The spectrum which 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 the spectrum was kept stationary by 

 means of a heliostat, and the needle was exposed seventeen 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 possesses 

 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. — Annales de Chimie, JVov, 

 1829. 



