216 EXPERIMENTS WITH 



some difference due to the bisulphide of carbon, which 

 affected their eyes, though not ours. 



I then thought it would be interesting to use, 

 instead of the bisulphide, a solution of sulphate of 

 quinine (^ dr. to 4 ounces), which differs from it in 

 many points, but agrees in cutting off the ultra-violet 

 rays. I used, as before, a layer about an inch thick, 

 which I placed over violet glass, and then placed by its 

 side the same coloured glasses as before. 



First, I took the red glass. 

 Obs. 1. About half the ants were under each. 

 „ 2. Most of them were under the red glass. 

 „ 8. About half under each ; rather more under the 

 violet glass and sulphate of quinine than 

 under the red glass. 



)J 4' 55 55 55 



I now took the dark-yellow glass instead of the red. 



Obs. 1 . Most of the ants were under the violet glass and 



sulphate of quinine. 

 55 2. All „ „ „ 



55 ''' 55 5J 55 55 



5, -i' 5, 55 55 yellow glass. 



55 ^* 55 55 5? 55 



„ 6. All the ants were under the violet glass and 



sulphate of (juinine. 

 „ 7. About half under each. 

 „ 8. Rather more under the violet glass and sulphate 



of quinine than imder the yellow glass. 



