3 1 * Imperial Institute of France. 



flattering prospects of future success, and excited peculiar 

 interest. It now consists of above a hundred members, 

 many of whom are well known literary characters ; — the 

 funds are in a very promising state, the hbrary is increasing, 

 and the zeal manifested by the members must render the 

 Society permanent*. 



It is the mtention of the Society to hold a converzatinne 

 during the winter months, which will afford the members 

 an ojiporlunitv of discussing those subjects which cannot 

 so wtil be do'ie at the general and nuire public meetings. 



The Soeietv atter the oration adjourned, and partook of 

 an elegant dinner, which was well attended. 



IMPERIAL INSTITUTE OF FRANCE. 

 [Continued from p. 1 J7.] 



On the llth of August 1811, M. Arajio communicated 

 to the class a memoir, the principal object of which was 

 to show that the luminous ravs received, in their passage 

 through several diaphanous bodies, new and peculiar modi- 

 ficalioi's. 



It will be recollected that, according to the experiments 

 of M. Mains, the character which distmguishes ihe direct 

 ray from that u hich has been polarized in us refiection upon 

 a diajihanous body, is owing to the former d.viding itself 

 constantly mto two fasciculi in its passage through a rhom- 

 boid of calcareous S};ar; whereas the latter undergoes, in 

 certain circumstances, but a single refraction. If, before 

 submitting the polarized rav to the analysis of a prism of 

 calcareous spar, we make it traverse either a plate of mica 

 or of sulphate of liaie, or certain plates of rock crystal, 

 we find that the emergent ray no longer resembles either a 

 direct rav of light or a polarized rav. Tins new ray will 

 be distinguished from the polarized light, by its always 

 giviuirtwo images ; and from the direct light, by the property 

 which it has of always dividing itself into two fasciculi, the 

 colours of which aic different and complementary. 



If a direct ray falls on a glass mirror, under an angle of 

 35|, and if without changing this inclinalion we turn the 

 mirror round the rav, the quantity of light which is re- 

 flected, and that which is retracted, will be constantly the 

 same. It resuhs on the contrary, from the experiments of 

 M. Malus, that when the miiror receives under the same 



* We forI)e,ir entering more fully into Mr. Pettigrew's elegant oration, as 

 vre understand that the Society intends to publish it. 



inclinatior\ 



