2 g THE FAIRY-LAND OF SCIENCE. 
represent the sun, and turn the globe slowly, so that 
the spot creeps round from the dark side away from 
the lamp, until it catches, first the rays which pass 
along the side of the globe, then the more direct rays, 
and at last stands fully in the blaze of the light. Just 
this was happening to our spot of the world as you lay 
in bed and saw the light appear ; and we have to learn 
to-day what those* beams are which fall upon us and 
what they do for us. 
First we must learn something about the sun itself, 
since it is the starting-place of all the sunbeams. If 
the sun were a dark mass instead of a fiery one we 
should have none of these bright cheering messengers, 
and though we were turned face to face with him every 
day we should remain in one cold eternal night. Now 
you will remember we mentioned in the last lecture 
that it is heat which shakes apart the little atoms of 
water and makes them float up in the air to fall again 
as rain ; and that if the day is cold they fall as snow, 
and all the water is turned into ice. But if the sun 
were altogether dark, think how bitterly cold it would 
be; far colder than the most wintry weather ever 
known, because in the bitterest night some warmth 
comes out of the earth, where it has been stored from 
the sunlight which fell during the day. But if we 
never received any warmth at all, no water would 
ever rise up into the sky, no rain ever fall, no rivers 
flow, and consequently no plants could grow and no 
animals live. All water would be in the form of snow 
and ice, and the earth would be one great frozen mass 
with nothing moving upon it. 
So you see it becomes very interesting for us to 
