1821.] Crystallized Bodies on Homogeneous Light, 



125 



Table IV. — Rochelle Salt, perpendicular to the Optic Axis, 

 Thickness = 0-194425 2;z. 



Corresponding 

 inclinations. 



201° 30' 

 207 10 



209 



210 30 

 -212 30 

 213 20 



215 25 



216 40 



218 



219 29 



220 58 



222 30 



223 45 



224 50 



226 10 



227 25 



228 30 



229 3 

 229 50 



231 20 



232 25 



234 . 



235 40 



236 23 

 238 50 

 240 12 



242 10 



243 40 



245 10 



246 50 



248 25 



250 40 



252 57 



256 5 



259 20 

 261 40 

 266 40 



330° 10 



Ordinary pencil. 



309 30 

 308 15 



307 

 306 10 



304 10 



302 20 



299 20 



296 15 



294'35 



292 55 



291 30 

 289 50 

 287 45 

 286 45 

 284 55 



282 30 



280 12 



277 25 



274 40 

 271 40 

 266 40 





White 



Exceeding pale blue 



Exceeding pale pink 



j V ery pale blue 



j Very pale pink 



I Very pale blue 



Pale pink 



iPaleblue 



Pink 



Pale blue ... 



Pink 



White 



Blue 



i Yellowish pink 



jPale greenish blue 



jBlue 



Pale pink 



iPale yellow 



iWhite 



[Bluish or greenish white. . 



iBlue 



I Violrt almost imperceptible 



i Pure white 



Exceeding pale yellow. . , 



ale yellow 



Very pale tawny orange . . 

 Fine purplish crimson .... 



Very pale purple 



Very pale green 



White 



Splendid crimson 



Pale purple 



Very pale green 



White 



Rich crimson 



Pale purple 



Pale blue green 



White 



Pink, rather pale 



White 



Pale blue 



Pale pink yellow 



Very pale blue 



Very pale yellow green. . . 



Pale lilac 



White 



Fine yellow green 



White 



Lilac 



White 



Fine yellow green 



White 



Pale lilac ^ 



White 



Green yellow 



Extraordinary. 



White 



Exceeding pale pink 

 Exceeding pale blue 

 Very pale pink 

 Very pale blue 

 Very pale pink 

 Pale blue green 

 Pale yellow pink 

 Blue green 

 Pale yellow pink 

 Greenish blue 

 Very pale purple 

 Yellow pink 

 Greenish blue 

 Yellowish pink 

 Pale pinkish yellow 

 Pale greenish blue 

 F3ark blue 

 Pale purple 

 Very pale violet pink 

 Very pale yellow 

 White 



Pure white 



A little violet 



Very narrow dark blue 



Blue, sombre, and pale 



Pale yellow green 



White 



Fine crimson 



Pale purple 



Very pale green 



White 



Rich crimson 



Pale purple 



Very pale green 



White 



Good pink, almost crimson 



Very pale jiurple 



Pale greenish blue 



White 



Pale yellowish pink 



Pale blue 



Very pale yellow 



Very pale lilac blue 



Yellow green 



White 



Fine lilac 



White 



Fine yellow green 



White 



Fine lilac 



White 



Fine yellow green 



White 



Pale lilac 



Remarks, &c. 



Poles PP' for 

 red rays 



Virtual poleS 



The middle 



tint 



