12 ON THE ACTION OF TRANSPARENT BODIES 
35. Copal, Gum. 
Gum Copal acts less powerfully upon green light than crown- 
glass. 
It acts a very little less powerfully on green light than flint- 
glass, 
36. Cummin, Oil of. 
This oil acts less powerfully upon green light than o7/ of la- 
vender, flint-glass, and crown-glass. 
It acts more powerfully upon green light than balsam of: 
Tolu. 
37. Diamond.. 
When diamond acts in opposition to oil of cassia, the uncor- 
rected colours are nearly of the same magnitude, and in the 
same situation, as when the oil of cassia is combined with flint, 
glass. Hence diamond has nearly the same action upon green 
light as flint-glass, 
38. Dill Seed, Oil of. 
This oil acts less powerfully upon green light than crown~ 
glass. 
It acts a very little less powerfully upon green light than- 
flint-glass. 
39. Ege, White of an. 
The white of an.egg acts more powerfully upon green. light: 
than crown-glass, topaz, muriatic. acid, nitric acid, and fluor 
spar. 
It acts less powerfully upon green light than water, and 
much less than sulphuric acid. 
40. Ethers. 
