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 (4 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. 
» 38- About half under each; rather more under the 
violet glass and sulphate of quinine than 
under the red glass. 
29 4. 29 2 ” 
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 ” ” ” 
39 3 29 ” 2 ” 
” 4. ” ” ” yellow glass. 
bh) 5 29 9 29 2” 
» 6. All the ants were under the violet glass and 
sulphate of quinine. 
» 7% About half under each. 
s» 8. Rather more under the violet glass and sulphate 
of quinine than under the yellow glass. 
