“A fine collection of rubies, madam,” said the shopkeeper, to whom her ladyship was a stranger.

“Yes,” she replied; “but curiously enough I have never actually counted them.  My mother once pointed out to me that if you start from the centre and count up one line, along the outside and down the next line, there are always eight rubies.  So I should always know if a stone were missing.”

[Illustration]

Six months later a brother of Lady Littlewood’s, who had returned from his regiment in India, noticed that his sister was wearing the ruby brooch one night at a county ball, and on their return home asked to look at it more closely.  He immediately detected the fact that four of the stones were gone.

“How can that possibly be?” said Lady Littlewood.  “If you count up one line from the centre, along the edge, and down the next line, in any direction, there are always eight stones.  This was always so and is so now.  How, therefore, would it be possible to remove a stone without my detecting it?”

“Nothing could be simpler,” replied the brother.  “I know the brooch well.  It originally contained forty-five stones, and there are now only forty-one.  Somebody has stolen four rubies, and then reset as small a number of the others as possible in such a way that there shall always be eight in any of the directions you have mentioned.”

There was not the slightest doubt that the Brompton jeweller was the thief, and the matter was placed in the hands of the police.  But the man was wanted for other robberies, and had left the neighbourhood some time before.  To this day he has never been found.

The interesting little point that at first baffled the police, and which forms the subject of our puzzle, is this:  How were the forty-five rubies originally arranged on the brooch?  The illustration shows exactly how the forty-one were arranged after it came back from the jeweller; but although they count eight correctly in any of the directions mentioned, there are four stones missing.

424.—­THE DOVETAILED BLOCK.

[Illustration]

Here is a curious mechanical puzzle that was given to me some years ago, but I cannot say who first invented it.  It consists of two solid blocks of wood securely dovetailed together.  On the other two vertical sides that are not visible the appearance is precisely the same as on those shown.  How were the pieces put together?  When I published this little puzzle in a London newspaper I received (though they were unsolicited) quite a stack of models, in oak, in teak, in mahogany, rosewood, satinwood, elm, and deal; some half a foot in length, and others varying in size right down to a delicate little model about half an inch square.  It seemed to create considerable interest.

425.—­JACK AND THE BEANSTALK.

[Illustration]

The illustration, by a British artist, is a sketch of Jack climbing the beanstalk.  Now, the artist has made a serious blunder in this drawing.  Can you find out what it is?