( 9 ) 



III. Corresponding Degrees in tlie 

 Fahrenheit and Centigrade 

 Scales. 



Cent. 



100 

 98 

 96 

 94 

 92 

 90 

 88 

 86 

 84 

 82 

 80 

 78 

 76 

 74 

 72 

 70 

 68 

 66 

 64 

 62 

 60 

 58 

 56 

 54 

 52 

 50 

 48 

 46 

 44 

 42 

 40 

 38 

 36 

 34 

 32 

 30 

 28 

 26 

 24 

 22 

 20 

 18 

 16 

 14 

 12 

 10 

 8 

 6 

 4 

 2 

 



- 2 



- 4 



- 6 



- 8 



- 10 



- 12 



- 14 



- 16 



- 18 



- 20 



Fahr. 



212 



208 



204 



201 



197 



194 



190 



186 



183 



179 



176 



172 



168 



165 



161 



158 



154 



150 



147 



143 



140 



136 



132 



129 



125 



122 



118 



114 



111 



107 



104 



100 



96 



93 



89 



86 



82 



78 



75 



71 



68 



64 



60 



57 



53 



50 



46 



42 



39 



35 



32 



28 



24 



21 



17 



14 



10 



6 



3 



- 



- 4 



IV. Refractive Indices, Dispersive 

 Powers, and Polarizing 

 Angles. 



(1.) Eefkactivb Indices. 



Diamond 



Phospliorua 



Bisulphide of carbon 



Flint glass 



Crown glass 



Eock salt 



Canada balsam 



Linseed oil (sp. gr. -932) 



Oil of turpentine (sp. gr. • 885) 



Alcohol 



Sea water 



Pure water 



Air (at 0° C. 760 mm.) 



(2.) DiSPEKSIVB POWEES. 



Diamond 



Phosphorus 



Bisulphide of carbon 



Flint glass 



Crown glass 



Kock salt 



Canada balsam 



Linseed oil (sp. gr. • 932) 



Oil of turpentine (sp. gr. • 885) 



Alcohol 



Sea water 



Pure water 



Air 



(3.) PoLAKiziNG Angles. 



Diamond 



Phosphorus 



Bisulphide of carbon 



Flint glass 



Crown glass 



Eock salt 



Canada balsam 



Linseed oil (sp .gr. • 932) 



Oil of turpentine (sp. gr. • 886) 



Alcohol 



Sea water 



Pure water 



Air 



P4 



