34 THE FAIRY-LAND OF SCIENCE. 
Thus we see there are two ways of touching any- 
thing at a distance ; 1st, by throwing some thing at it 
and hitting it ; 2nd, by sending a movement or wave 
across to it, as in the case of the quivering boards and 
the air. 
Now the great natural philosopher Newton thought 
that the sun touched us in the first of these ways, and 
that sunbeams were made of very minute atoms of 
matter thrown out by the sun, and making a perpetual 
cannonade on our eyes. It is easy to understand 
that this would make us see light and feel heat, just as 
a blow in the eye makes us see stars, or on the body 
makes it feel hot : and for a long time this explana- 
tion was supposed to be the true one. But we know 
now that there are many facts which cannot be 
explained on this theory, though we cannot go into 
them here. What we will do, is to try and under- 
stand what now seems to be the true explanation of 
a sunbeam. 
About the same time that Newton wrote, a Dutch- 
man, named Huyghens, suggested that light comes 
from the sun in tiny waves, travelling across space 
much in the same way as ripples travel across a pond. 
The only difficulty was to explain in what substance 
these waves could be travelling : not through water, 
for we know that there is no water in space nor 
through air, for the air stops at a comparatively short 
distance from our earth. There must then be some- 
thing filling all space between us and the sun, finer 
than either water or air. 
And now I must ask you to use all your imagina- 
tion, for I want you to picture to yourselves something 
