before, and he said angrily, "You do nothing but wag your tail, wag your tail, wag--your--tail" and suddenly he found that he had written down wagtail without thinking. And the little bird has been called a wagtail ever since. [Illustration] "And it does wag its tail all the time," says the Elf. It really does. We see it flit about the shores of the stream, first a little this way, and then a little that, and every time it perches its tail wags up and down, up and down, like a tiny see-saw that has lost its other end. Sometimes late in the summer we see yellow wagtails by the stream, and they are even prettier than the grey ones, the very daintiest of little fairy birds. But in autumn, both the grey wagtails and the yellow ones fly away over seas like the swallows, and we do not meet them by the stream side till next year. IV LAKE AND RIVER One month in every year the Imp and the Elf and I go to stay in a farmhouse close by the shores of a lake, that is bigger than the biggest pond you have ever seen. Out of the lake flows a river, that is bigger than the biggest stream. But when we go there we always feel very much like we do when we go over the common to the duck pond, or follow the beck from the woodland to the valley. Only, now, instead of lying on the bank at the side of the water, we go in a boat, and row out with the water lapping round us. It is as if we were in an enormous ship of our own, and quite safe, for the boat is so broad in the beam that not even the Imp or the Elf could tumble out if they tried. Of course we are pirates, and Sir Francis Drakes, and vikings, and other sea rovers, from time to time. I often find that I have been a villainous pirate mate, when, for all I knew, I had been peaceably reading a book in the stern, and we none of us know when we set out in the morning what manner of gay adventures we shall fashion for ourselves upon the water. But, if I were to tell you about all that, I should have no room left in which to write of the water folk, and that would never do.