14 



Prof. A. Kundt on the Indices 



Silver Iodide. 



No. 



8. 



a. 



n. 



Remarks. 



Red. 



White. 



Blue. 



Eed. 



White. 



Blue. 



1 

 2 

 3 



16-64 

 45-86 

 67-59 



... 



+21-71 

 +53-07 

 +98-50 





... 



2-30 



2-16 

 2-46 





The prism was obtained by 

 iodizing a silver prism. 





Iron Oxide. 





1 



2 



1209 

 25-71 



+9-38 



+13-41 



+28-66 



+16-40 



1-78 



2-11 

 212 



2-36 



The oxide prisms were ob- 

 tained by heating the 

 iron prisms to faint 

 redness. 



Nickel Oxide. 



1 



24-27 



+28-57 



+29-88 



+33-66 



2-18 



2-23 



2-39 



Obtained by heating a 

 nickel prism to bright 

 redness. 



Bismuth Oxide. 



1 



20-82 





+ 1894 







1-91 





Obtained by heating a bis- 

 muth prism to redness. 

 The dispersion was small, 

 so that it could not be 

 determined with certainty. 



Copper Oxide. 



1 



12-72 



+20-75 



+23-44 



+2771 



2-63 



2-84 



3-18 



Obtained by heating a cop- 

 per prism to faint redness. 



Platinum mixed with Platinum Oxide. 



The prisms obtained by disintegration of platinum foil 

 heated to redness by a galvanic current are a mixture of 

 metallic platinum and oxides of platinum, which, as mentioned 

 above, are only converted into pure platinum by heating. 

 Since the composition is no doubt different in different prisms, 

 there is little interest in determining the refraction of these 

 mixtures, I give only a few values, as the indices are un- 

 usually large. 



