6 ON THE ACTION OF TRANSPARENT BODIES 



acid may be regarded as exercising a greater action upon the 

 green rays than the glass. 



When the nitrous acid acts in opposition to the muriatic acid, 

 no uncorrected colour is perceived. 



8. Acid, Phosphoric. 



Phosphoric Acid acts very much more powerfully upon green 

 light than Jlint-glass. The secondary spectrum is very vivid 

 and beautiful. 



It acts much more powerfully upon green light than crown- 

 glass. The secondary spectrum is very distinct. 



It acts much more powerfully upon green light than the mu- 

 riatic acid. 



Its action upon green light is nearly as small as that of sul- 

 phuric acid. By inclining the phosphoric acid prism, the uncor- 

 rected green light appears towards its vertex ; but by inclining 

 the sulphuric acid prism, it does not appear. Hence the phos- 

 phoric acid acts a little more powerfully upon green light than 

 the sulphuric acid. 



9. Acid, Phosphorous. 



Phosphorous Acid acts more powerfully upon green light 

 than Jlint-glass, crown-glass, rock-crystal, or water. 



10. Acid, Prussic. 



Prussic Acid acts much more powerfully upon the green rays 

 than Jlint-glass. 



It acts more powerfully upon the green rays than crown- 

 glass. 



When it acts in opposition to blue topaz, no uncorrected co- 

 lour is visible. The refracting angle, however of the topaz 



prism, 



