oie 
‘a 
M. C. Lea-on certain phenomena of Light, 367 
entirely different. And farther, he attempted no seplanation 
of the elective tendencies of these bodies as respects heat, but 
simply recorded the fact. 
simultaneously the blue, the latter diffused. 
Case Tuirp.—Reddish and bluish light, both diffused, are 
simultaneously visible. ; 
he simple existence of this third class disproves the expla- 
nation usually received and quoted above, for that explanation 
affirms that the red light tends to transmission, and the 
to diffusion. I shall endeavor presently to show that in one of 
the very instances usually quoted, the red and blue light un- 
dergo diffusion equally. 
_ Case first.—Production of a yellow or red beam of direct 
light, in the absence of blue. 
into the darkened room, let the beam fall upon the mirror lying 
horizontally or nearly so, upon a table, so as to be reflected 
‘tay which now passes through the colorless glass is no longer 
white, but of a deep yellow color. It is necessary in order that 
this experiment should fully succeed, that the grinding should 
= beextremely fine. Ordinary ground glass will not answer at 
al] & ; 
ee ficult t rocur la ound finely 
As it is extremely difficult to procure ite ik ced in 
ss enough, it is fortunate that the same result can be produc 
many different ways. One of the best, is the imprisonment of 
__* The glass must be merely “ greyed,” not ground, and with the finest emery: 
