“James, my boy,” said Mr. Marple “do you know why there should be winter and summer?

No, father, I really cannot tell. I know that in England the sun was higher up in the day, and that he stopped up longer in summer than in winter. But then as I believed that the sun ran about as he liked, I was not surprised at his change of place. Now, however, I am very anxious to know more about this subject.

When were we in the circle of the Pleiades, that is, the place where at some time or other of the twenty-four hours they would be overhead?

O, that was long before we got to the equator.

Yes, it was about 1500 miles to the north[Pg 24] of us. Now we are in the circle of the Virgin cluster.

But the Bull and the Virgin belong to the twelve constellations, of which we were talking, forming a broad circle, along which the sun appears to travel.

True. But they are not in an upright circle. Their line will cross our equator Line.

If that be it, the sun does not appear, then, to go round us over the equator.

No; for if it did, it would be seen overhead at that place every day at twelve o’clock; whereas it shifts its course continually. One day it is over one part at noon, and upon another day over another part.

Why, if the circle of the Zodiac be inclined to the circle of the equator, it will cross it in two places. I suppose that is the reason why, on the celestial globe, one constellation, as the Virgin, is over the equator circle; others, as the Bull, over some place to the north of it; and some others, as the Scorpion, to the south.

You guess rightly.

Then if that be it, the sun must appear to cross the equator twice in the year.

It does so on the 21st of March and 23rd September. These are the vernal or spring equinox, and the autumnal equinox. March is the vernal equinox of London, or equal day and night in spring; but it is the Australian autumnal equinox. In September the Australias have the spring equinox, and the English the autumnal. The sun is seen[Pg 25] overhead to the furthest north on the 21st of June, and to the furthest south on the 21st of December.

Why, the first is the summer of England, and the last the winter. Then I suppose that is the reason why in summer the sun looks so high up at noon. Then in winter, as it is shining more over parts south of the equator, the north would neither see nor feel so much of him.

That is correct. You now see why the Australian summer is at the time of the English winter.

Yes, father; because they are on opposite sides of the equator. But you know that the sun does not really move about like this. I want to know what does move.

The earth, to be sure.

I understand that; but neither the rotundity nor motion seems to explain this mystery of the Zodiac. But let me see. When the world swings round the master light, is it obliged to keep bolt upright—north pole up and south pole down?

How would your equator then be, James?

Right opposite the sun. But that will not do, for it is not always opposite to the sun. Perhaps the world goes waddling along like a duck, first on one side a little bit, and then on the other. This would bring the sun opposite to either place.

It would be a very regular waddle. We will try your scheme. Pick up that round wooden ball there. Carry it round the capstan, and[Pg 26] see whether by twisting it from one side to the other you can keep the south pole shone upon for six months, and the north pole shone upon for the other six months.”

James now makes a trial. But after all sorts of turns he failed in producing the English winter and summer in the proper time and for the proper length of time.

“I must give it up, father.

Just slant your ball a little out of the perpendicular, and carry it round your sun without moving it from its position.

Capital! It explains the whole. When it was in front of the capstan, the south pole was toward it; that was the Australian summer. When I went to the right side, neither end was inclined toward it; this was the sun over the equator. When I came to the back of it, the north pole was toward it; this was the English summer. When I reached the left side, my equator was opposite to it; this was the sun’s second crossing of the Line. When I got to the front again, there was my south pole pointing to the capstan again.

Then you really understand the seasons. Of course the spring in England is the autumn of Australia. But I have something else to recall to your recollection. Have you forgotten the old church on the hill at home?

No, father, and never shall. How pretty it looked when the sun rose over it upon a fine spring morning, with the birds all alive with their song, and the bees down upon the flowers!

[Pg 27]Did the sun rise over the church at hay harvest?

No; I remember then it came up from behind the squire’s house to the left of it.

Where was the sun first seen upon a cold winter’s morning?

Aye, I fancy I see his red face looking lazily over the parsonage to the right of the church, and that when we had done breakfast, too.

How came the sun to jump about in that manner?

Why, do you see, he did not hop from one side to the other. He would get a little further from the church each morning till he rose over the squire’s house: then, as if ashamed, he seemed to creep back to his old place. Afterwards he appeared to take it into his head gradually to get on to the parsonage, and then he would once more turn to the church.

Which was on the north-side of the church, James?

The squire’s house. Now, I think I can explain all without your questions this time, my dear father.

Then go on by all means.

The sun rose over the squire’s house in summer, for that was the north side; the north pole was then inclined to the sun. At spring it was half-way between the squire’s and the parsonage; this was the sun over the equator. In winter the sun rose at the furthest part to the south; this was where the north pole was turned away, and the south side turned to the sun.

[Pg 28]Well, then, you have satisfactorily explained the seasons.”