298 



CATALOGUE. ?HYSICAt OPTICS. 



Index of refraction. 



Opium. W. 



Mica. W. 



Plate glass, or coach glass, sp. gr. 



2.76. C. - - 1.573 



Phosphorus. W. - - 1.579 



Horn. W. 



Flint gliiss. W. 



C 1 .583 

 C 1.586 



Benzoin. W 



Guaiacum. W. - - 1.596 



Balsam of Tolu. W. - I.60 



White flint glass, sp. gr. 3.29- C. 1 .600 



A yellow pseudotopaz. C. 1.643 



Sulfate of barytes (double). W. 1.646 



Iceland spar, strongest. W. 1.657 ^ 



Glass, of lead 1, flint 4. C. 1.664 

 Gum dragon. W. 



Glass, tinged red by gold. C. 1.715 

 -Glass, of lead 1, flint 2. C. 1.724 

 Glass, of lead 3, flint 4. C. 1.732 

 White sapphire. W. - I.768 

 Glass, of lead 1, flint 1. C. 1.787 

 Muriate of antimony, variable. W. 

 Arsenic. W. (A good test). 1.811 

 Spinelle ruby. W. - 1.812 

 Glass, of lead 2, flint 1. C. 1.830 

 Jargon. W. - - 1.95 

 Glass of antimony. W. - 1.98 

 C. - (1.89) 

 Glass, of lead 6, sand 1. W. Doubt- 

 ful. - - 1.987 

 Glass, of lead 3, flint 1. C. 2.028 

 Native sulfur (double). W. 2.04 

 Scaly oxid of iron. Y. About 2.1 

 Oxid of lead, by induction. Y. 2.15 

 Plumbago. W. 

 Diamond. Newton. - 2.44 



Rochon. - fi.755 - 



From Dr. WoUaston's mode of obserration, it may be in- 



ferred that his numbers belong correctly to the extreme 

 red rays. 



Table of the order of Dispersive Powers, from 

 Wollaston, the Numbers from llochon and 

 from Cavallo's table. 



Sulfur. W. 



Glass, of lead 6, sand 1. W 



Glass, of lead 3, flint 1. r.2.028. 7.09 



Glass, of lead 2, flint 1. r. 1.830. 5.24 



Glass,oflead 1, flint 1. r.1.787. 4.82 



Glass, of lead 3, flint 4. r. 1 .732. 3.25 



Glas», tinged by gold, r.l .7 15. 2.90 



Glass, of lead 1, flint 2. r. 1 .724. 2.65 



Glass, of lead I, flint 4. r.1.664. 2.00 



Balsam of Tolu. W. 



Oil of sassafras. W, 



Muriate of antimony. W. 



Guaiacum. W. 



Oil of cloves. W. 



Flint glass, r.l. 6. - - 1.80 



Flint glass. W. 



Colophony. W. 



Canada balsam. \y. 



Oil of amber. W. 



Jargon. W. 



Oil of turpentine. W. 



Copal. W. 



Balsam of capivi. W. 



Anime. W. 



Iceland spar. W. 



Iceland spar r. 1.562 Cl.69 



1.625 12.33 



Amber. W. 



Diamond. W. 



Diamond, r.2.755. - fl.86 



Alum., W. 



Plate glass, r. 1.573 - 1.65 , 



Brazil pebble, r. 1.532. - 1.59 



Nitric acid, r.1.412. - I.54 



Plate glass. Dutch. W. 



