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 sulj)hate of 

 quinine (i 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. 

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

 violet glass and sulphate of quinine than 

 under the red glass. 

 4 



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. 

 2 All 



5> "• 5» » ?5 J' 



„ 4. „ „ „ yellow glass. 



?» ^' 5J 5> 55 ?5 



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



sulphate of quinine. 

 „ 7. About half under each. 

 „ 8. Rather more under the violet glass and sulphate 



of quinine than under the yellow glass. 



