USB OF THK IMAGINATION. 427 
easily as a ripple produced by a sea-bird's wing; and in 
the presence of large reflecting surfaces, the existing 
differences of magnitude among the waves of ether may 
disappear. Buc supposing the reflecting particles, instead 
of being very large, to be very small in comparison with 
the size of the waves. In this case, instead of the whole 
wave being fronted and thrown back, a small portion only 
is shivered off. The great mass of the wave passes over 
such a particle without reflection. Scatter, then, a hand- 
ful of such minute foreign particles in our atmosphere, and 
set imagination to watch their action upon the solar waves. 
Waves of all sizes impinge upon the particles, and you see 
at every collision a portion of the impinging wave struck 
off; all the waves of the spectrum, from the extreme red 
to the extreme violet, being thus acted upon. 
Eemembering that the red waves stand to the blue much 
in the relation of billows to ripples, we have to consider 
whether those extremely small particles are competent to 
scatter all the waves in the same proportion. If they be 
not and a little reflection will make it clear that they 
are not the production of color must be an incident of 
the scattering. Largeness is a thing of relation; and the 
smaller the wave, the greater is the relative size of any 
particle on which the wave impinges, and the greater also 
the ratio of the portion scattered to the total wave. A 
pebble, placed in the way of the ring- ripples produced by 
heavy raindrops on a tranquil pond, will scatter a large 
fraction of each ripple, while the fractional part of a larger 
wave thrown back by the same pebble might be infini- 
tesimal. Now we have already made it clear to our minds 
that to preserve the solar light white, its constituent pro- 
portions must not be altered; but in the act of division 
performed by these very small particles the proportions 
are altered; an undue fraction of the smaller waves is 
scattered by the particles, and; as a consequence, in the 
scattered light, blue will be the predominant color. The 
other colors of the spectrum must, to some extent, be 
associated with the blue. They are not absent, but 
deficient. We ought, in fact, to have them all, but in 
diminishing proportions, from the violet to the red. 
We have here presented a case to the imagination, and, 
assuming the undulatory theory to be a reality, we have, 
I think, fairly reasoned our way to the conclusion, that 
