92 ROBERT STANLEY McEWEN 
per cent, then the red flask transmits 103 per cent, the green 64 
per cent and the violet 51 per cent. The fact that the red flask 
actually transmits more than the white is explained by the fact 
that the layer of clear water was slightly thicker than the red 
solution. It will be noted, however, that in the visible spectrum 
the red is somewhat less than the white, while the green and the 
violet are approximately equal. 
The first colored light experiments performed were under- 
taken in the Zoological Laboratory of Western Reserve Univer- 
sity, Cleveland, Ohio, during the summer of 1916. After some 
preliminary experimentation it was decided to make use of 
wo Curves showing relation between galvanometer 
deflections and scale readings 
a 
> 
\eRed Bottle, Area—65.4 cm 
\ 
UJ 
eet te Light, Area—Sl.7. e177} 
420| Areasinyisible Spectra 
White Lignt—is crm 
Red Bottle — 9.8cm* 
Grecia Bottle—/.7 om 
Blue Bott/e—/-4em* 
Def lectiovns 
7ra 
Spectr 
Vis/ ble 
Ey 6 4} 
Seale readings 
Graph 4 
