BISULPHIDE OF CARBON. 213 



2. The greater number were under the violet 



glass and bisulphide. 

 2.30 



3. Almost all were under the glass and bis:;lphide. 



The addition of the bisulphide thus caused the violet 

 glass to be distinctly preferred to the chlorate of copper. 



I then took a solution of sulphate of nickel, almost 

 exactly the same tint as, or a shade paler than> the 

 chlorate of copper. 



At 3.45 the ants were under the violet glass and 

 bisulphide. 



Here the efifect was even more marked. 

 I then took some saffron 1 inch in thickness and of 

 H deep-yellow colour. 



12.45 The ants were about half under each. 



1. Most of the ants were under the violet glass 

 and bisulphide. 



1'15 „ „ „ 



2. Most of the ants were under the saffron. 



Here, again, we have the same result. 



I then tried the different-coloured glasses, all of 

 which, as I had previously found, are unmistakably 

 preferred to the violet. It remained to be seen what 



