It was upon a lovely evening, when off the coast of South America, ready to slip across by the side-help of the South-east Trades to the Cape of Good Hope, that Mr. Marple found his son at his old post.

“Now then,” said he, “my star-gazing boy, are you quite sure that none of them have run away since last night?

I am not sure of that, father; for ever since you proved that the Fixed stars were not fixed, I think I might some day find a bright friend gone on a visit to another universe somewhere; perhaps, getting into such agreeable society as to have no wish to come back again to our visible universe; or, maybe, to pop back again in his place.

It so happens, James, that what you have imagined, really takes place. Some stars do really disappear, to return, or not; and others,[Pg 58] wholly strangers to us, come within observation.

That is the queerest thing you have told me yet. What droll fellows the stars are, after all! How they do wriggle about, polkaing here, doubling there, and fielding about like boys at cricket. I shall never be surprised at any funny trick you ascribe to them.

To begin with the Variable stars, of which there are known about one hundred. There is Mira, which is invisible five months in the year. It goes and comes again.

Where could it have got to?

Some think it revolving round a dark object; and, of course, becoming invisible when on the other side from us. One passes through three magnitudes in one month.

But I must give you the history of such a curious star in the Whale. For two weeks you might see it a noble star of the second magnitude. It gradually dims, till it goes fairly out of sight in three months. For five weeks you see nothin............