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. The ants were about equally divided. 

 2. Most of them were under the red glass. 

 3. Nearly equally divided ; 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 3. ,1 



4. yellow glass. 







6. All the ants were under the violet glass and 



sulphate of quinine. 

 7. Equally divided. 



8. Kather more under the violet glass and sulphate 

 of quinine than under the yellow glass. 



