286 SIB JOHN ITJBBOOK ON ANTS, BEES, AND WASPS. 



place altogether at the surface of the liquids, so that it is not ne- 

 cessary to use any large quantity. I poured them into shallow 

 glass cells about g inch deep, which I put, as before, over the ants. 

 If now they were aifected mainly by the chemical rays, it must 

 appear to them to be dark under these solutions. This, however, 

 was not the case. The solutions seemed to make no difference 

 to them. I also tried quinine and uranium glass with the same 

 eflFect. 



In order to ascertain what colours were transmitted by these 

 several media, I then tested them with the spectroscope, and 

 with the followuig results : — 



The violet glass transmitted Tiolet, blue, some green and yellow to about the line 

 D in the spectrum or a trifle beyond. 

 „ „ (double) transmitted violet and blue with tinge of red. 

 green glass 



yellow 



a 



rod 

 purple 



Amm. sulph. of copper (blue) transmitted violet and blue only. 



Chloride of copper .. . (green) „ green, an edging of blue, and faint 



yellow with an edging of orange. 



Saffron „ every thing except violet and blue. 



Bichromate of potash (orange) „ red, orange, yellow, and very little 



green. 



1. yellow^ " } " ™''^' °''™g^' yellow, and green. 



Fuohsine (carmine) ,, red only. 



Solution of carmine .. „ „ „ 



Solution of iodine „ „ red, orange, and a very little yellow. 



But though the ants so markedly avoided the violet glass, still, 

 as might be expected, the violet glass certainly had some eifect, 

 because if it was 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 ammonio- 

 sulphate of copper, which is very similar, though perhaps a little 

 more violet, and arranged the deptli of the fluid so as to make it 

 as nearly as possible of the same depth of colour as the glass. 



