"I wonder," he said, "if you would do me a favour.

I have scores of nephews and nieces, and also many friends, in America, to whom I want to send picture postcards.

Now," he continued, "listen here.

Here's seven shillings, one for each of you; and here's a five-shilling piece.

Now I am going to give you each a shilling to buy picture post cards with, and I want you each to buy them separately--in different shops if you like--and then bring them back to me, and I'll give the five-shilling piece to the one who has what I think the best collection.