we 
Prof. O. N. Rood on a New Theory of Light. 183 
it was therefore fairly to be expected that if the disc was really 
tansmitting red light, the plate of glass would do the same. The 
result was different; through the glass the dise appeared of a 
bright greenish-blue color. This experiment is very easy to 
make, and the effect is brilliant. 
_Flates of glass of other tints were now employed ; the results 
are given below 
Medium, Tints of the Disc 
Yellow glass, Violet, 
Green“ Green, neutral, or faint red, 
Red x3 Red, neutral, or faint green. 
aaah of the complementary tint, more or less mingled wit 
@ or 
aring now shown that, contrary to Mr. Smith’s supposition, 
the light transmitted by the revolving disc is really white, let us 
Rotice some of its effects on the eye 
Py diameter and perforated with four slits 7° 12’ in the width was 
_~ *etin rotation, and the bright sky viewed through it; the eye 
of the observer. being immediately behind the disc. With a 
_ ‘Tate of 114 revolutions per second, the appearance 2. 
of the window was as in fig. 2; a central spot was 
colored piuish-green, the rest of the field was pur- co 
PURPLE 
8 long as the rate of revolution continued the ' 
or shadow was fringed with a narrow, faint 
bas spot 
border, indicated by the dotted line. 
