Many years ago Dr. Jenner procured several swifts from a farmhouse in Gloucestershire, and marked them by cutting off two claws from the foot of twelve of them. Next year their hiding places were examined in the evening, when the birds had gone to roost, when Dr. Jenner found many of the birds he had marked by cutting off the two claws. For two or three consecutive years he examined their nesting places, and always found some of his marked birds. At the end of seven years a cat brought a swift into the farmer's kitchen, and this was one of those which Dr. Jenner had marked. Now, Willy, I will ask you a question in geography. The swallow family visits this country from Africa. What sea, then, must the birds fly across? "The Mediterranean, papa." Quite right; and now can you tell me the narrowest part of the Mediterranean Sea? "The Straits of Gibraltar." Right again; and there the passage is about five miles wide; and at Gibraltar swallows, swifts, and martins are often seen as well as several other bird-visitors of this country. People on board ship have seen swallows a long way from land passing between Europe and Africa. Sometimes the poor birds are so tired from their flight that they are obliged to rest on the masts, yards, and rigging of the vessels. This often happens when the weather is hazy. Holloa, Jack, what is that splash in the water about six yards off? Keep quiet, and we shall see what it was. Ah! it is one of my friends, the water-voles; I see the rogue, with his large yellow teeth and black eyes. Do you see? He is on the other side of the drain, nibbling away at something. People generally call him a water-rat, but he is no relation at all to a rat, nor is he an injurious creature like it. "Well, but papa," said Willy, "the lads in the village always kill these water-rats, as they call them, whenever they can. I suppose they take them for common rats. Do you say they do no harm?" Very little, water-voles will not eat young chickens and ducklings; nor do they find their way into stacks and consume the corn; their food is entirely confined to vegetables, such as the roots and stems of water-weeds. I feel, however, pretty sure that the water-vole is fond of beans, and will occasionally do some mischief where a field of newly-sown beans adjoins the river or stream, in the banks of which these animals form their holes. I will clap my hands, and off our little friend with his dusky coat starts, diving under the water, whence when he comes out he will probably escape into a hole on the bank. Some day I will show you the skulls of a water-vole and a rat, and you will see there is a great difference in the form and arrangement of the teeth, and that the first-named animal is not, as I said before, related to the rat. The water-vole is really a relative of that interesting creature you have often read of--I mean the beaver. "Well, papa," said Jack, "I am tired of sitting here, let us