1881.] 



Some Experiments on Metallic Reflexion. 



495 



Eed light. Yellow light. Blue light. 







P 



.1. 



A. 



P.I. 



A 





P 



I. 



A 









o 





o 





o 





o 











o 





Silver in air. <j 



fpll. 



76 



03 



36 



11 



75 



20 



35 



52 



72 



07 



31 



44 



Lppd. 



76 



19 



29 



26 



75 



35 



35 



30 



72 



32 



47 



38 







76 



11 



32 



43 



75 



27 



35 



41 



72 



19 



39 



28 



Silver in 



r P U. 



73 



58 



37 



34 



72 



56 



36 



34 



69 



48 



31 



14 



water. 



\ ppd. 



74 



03 



30 



57 



73 



13 



35 



52 



69 



59 



48 



14 







74 



01 



34 



11 



73 



05 



36 



13 



69 



53 



39 



29 



Silver in carbon . 



fpll. 



73 



04 



33 



50 



72 



59 



37 



48 



68 



49 



31 



44 



tetrachloride. 



lppd. 



73 



09 



31 



17 



72 



38 



37 



07 



68 



19 



49 



44 







73 



07 



34 



58 



72 



47 



37 



27 



68 



34 



40 



30 



The azimuths for silver in air and water with yellow light were so 

 close to one another, that the mean was taken in these two cases as 

 the principal azimuth. 



The determinations of the reflexion constants of the silver plate 

 made by the two different methods agree fairly well together, but are 

 not in accordance with subsequent observations made with films of 

 chemically deposited silver, or with M. Jamin's experiments (" Cours 

 de Physique," edit. 1866, vol. iii, p. 693), the principal incidences being 

 somewhat too high, and the principal azimuths having different values 

 for light of different refrangibilities, instead of being nearly the same 

 for all kinds of light. 



The plate having been polished with rouge, and having, as has 

 already been mentioned, a reddish tinge, due in all probability to 

 minute particles of the powder having become embedded in its surface, 

 it appeared possible that the difference in the values of the azimuths 

 for the three kinds of light might be due to the rouge ; the plate was 

 therefore dismounted and well polished with putty powder, which was 

 chosen as being nearly white, and then the measurements repeated in 

 the usual manner. 



Silver in 

 water. 



Silver in 

 water. II. 





Eed li 



Lght. 



Yellow 



light. 



Blue light. 





P.I. 



P.A. 



P.I. 



P.A. 



P.I. 



P.A. 









o / 









Plate at A. 



78 26 



44 02 



75 



44 11 



71 28 



42 56 



Plate at B. 



74 33 



43 41 



74 14 



43 16 



71 39 



43 04 



Mean value 



76 29 



43 51 



74 37 



43 22 



71 33 



43 



Plate at A. 



76 18 



44 27 



72 38 



44 54 



67 15 



43 10 



Plate at B. 



71 37 



43 46 



71 22 



43 20 



68 23 



43 05 



Mean value 



73 57 



44 06 



72 



44 07 



67 49 



43 07 



Plate at A. 



75 53 



43 59 



73 02 



44 37 



66 27 



43 51 



Plate at B. 



71 53 



43 59 



71 59 



43 46 



67 42 



43 41 



Mean value 



73 53 



43 59 



72 30 



44 11 



67 04 



43 46 



