“It’s just like the hot water bottle mother kept in my bed that time I had a chill after swimming,” said Paul. “The hotter it was before she put it in the bed the slower it cooled off.”
“That’s the idea,” said Uncle Henry, “the longer the sun shines on any place on the earth the hotter it gets, and when the nights are as short as they are in Summer the place hasn’t long to cool off before it is round in the sun’s hot rays again. Now do you see why Summer is hotter than Winter?”
The children did.
“There’s one thing I don’t understand, though,” said Peter. “Why are there different stars in the sky in Winter than there are in Summer?”
“That’s easy to answer,” said Uncle Henry. “Look at Paul again—first when it’s ‘night’ on his face on the ‘Summer’ side of the lamp, and then when it is ‘night’ on his face on the ‘Winter’ side of the lamp.
“At ‘night’ in Summer Paul looks at the pictures on one end of the room. The cardboard brim, or ‘plane of the equator,’ is slanted up, above the ‘plane of the ecliptic.’”
This picture shows how Paul looked.
“But in Winter, at ‘night,’ Paul looks at quite different pictures, at the other end of the room. The cardboard brim is slanted down, below the level of the ‘plane of the ecliptic.’ This is why the path of the Winter Signs crosses the sky higher up than the path of the Summer Signs. In both Winter and Summer you must imagine the cardboard brim to be as transparent as glass, for the ‘plane of the equator’ is in reality only imaginary.”