36 THE FAIRY-LAND OF SCIENCE. 
and you can imagine how in the same way waves 
travel over the ether from the sun to us. 
Straight away from the sun on all sides, never 
stopping, never resting, but chasing after each other 
with marvellous quickness, these tiny waves travel 
out into space by night and by day. When our spot 
of the earth where England lies is turned away from 
them and they cannot touch us, then it is night for us, 
but directly England is turned so as to face the sun, 
then they strike on the land, and the water, and warm 
it ; or upon our eyes, making the nerves quiver so that 
we see light Look up at the sun and picture to 
yourself that instead of one great blow from a fist 
causing you to see stars for a moment, millions of 
tiny blows from these sun-waves are striking every 
instant on your eye ; then you will easily understand 
that this would cause you to see a constant blaze of 
light. 
But when the sun is away, if the night is clear we 
have light from the stars. Do these then too make 
waves all across the enormous distance between them 
and us ? Certainly they do, for they too are suns like 
our own, only they are so far off that the waves they 
send are more feeble, and so we only notice them 
when the sun's stronger waves are away. 
But perhaps you will ask, if no one has ever seen 
these waves nor the ether in which they are made, what 
right have we to say they are there ? Strange as it may 
seem, though we cannot see them we have measured 
them and know how large they are, and how many 
can go into an inch of space. For as these tiny waves 
are running on straight forward through the room, if 
we put something in their way, they will have to run 
