194 DISLIKE OF VIOLET. 
I should rather say, inversely as they would, on a 
photographic plate. It might even be alleged that the 
avoidance of the violet glass by the ants was due to their 
preferring rays transmitted by the other glasses. From 
the habits of these insects such an explanation would be 
very improbable. If, however, the preference for the 
other coloured glasses to the violet was due to the trans- 
mission and not to the absorption of rays—that is to 
say, if the ants went under the green rather than the 
violet because the green transmitted rays which were 
agreeable to the ants, and which the violet glass, on 
the contrary, stopped—then, if the violet was placed 
over the other colours, they would become as distasteful 
to the ants as the violet itself. On the contrary, how- 
ever, whether the violet glass was placed over the others 
or not, the ants equally readily took shelter under them. 
Obviously, therefore, the ants avoid the violet glass 
because they dislike the rays which it transmits. 
But though the ants so markedly avoided the violet 
glass, still, as might be expected, the violet glass cer- 
tainly had some effect, because if it were put over the 
nest alone, the ants preferred being under it to being 
under the plain glass only. 
I then compared the violet glass with a solution 
of ammorio-sulphate of copper, which is very similar in 
colour, though perhaps a little more violet, and arranged 
the depth of the fluid so as to make it as nearly as pos- 
sibie of the same depth of colour as the glass, 
