require water,” said Tom. “That whenever you cut off their water supply they die.”

“Quite right, Tom. We shall see by and by that plants are always giving off a great deal of water to the air from their leaves.[1] Where do they get this water from?”

“It must be from the soil,” said Frank.

“It must be,” said Uncle George. “If we keep a plant in a pot without watering it, it soon dies. All the water it contains will by and by travel up to the leaves. It passes out through tiny pores in the leaves into the air. If no more water comes up from the soil, the plant withers and dies. The roots of plants search the soil in all directions for water. And in this water there is but little plant-food. We saw this when we boiled away the clear water which covered the soil in the glass.

“If we boil away some water from the tap, we shall find some solid matter left behind in the dish. Thus we see that in order to get a small quantity of food, plants take up a great quantity of water from the soil. Most of the water is sent into the air from the leaves. But the food stuff remains in the plant, just as it did in the dish.

“Now I am going to show you how this water gets into the plant. Look at these little seeds on the damp blotting-paper!

“Each seed has a small plant with a long root, and small, stout green leaves. Look at the roots and tell me what you see?”

“They are covered with silky stuff,” said Frank.

“Yes. Now take this glass, which will make things look bigger than they really are, and look at the roots once more.”

“The silky stuff is a number of fine hairs,” said Frank.

THE OTTER

FIELD-MICE

“That is quite right, Frank,” said Uncle George. “These are the root-hairs. Each of these hairs is a long bag or sac, of very thin skin. It is filled with a liquid called sap, which is slightly denser, or heavier, than the water in the blotting-paper. Now, do you see how a plant takes food from the soil, when it is growing in the garden or in a field?”

“Yes, I think I do,” said Frank. “The water in the soil contains very little plant-food. The water inside the tiny sac contains very much.”

“And what have you to say, Tom?”

“One of these liquids is denser than the other,” said Tom. “Both are separated by a thin skin. The lighter liquid outside the sac will pass into it quickly, while the heavier liquid will pass out slowly.”

“Bravo! Tom!” said Uncle George. “I couldn’t have given a better reply myself. The water from the soil passes in quickly. The sap from the inside of each root-hair passes out slowly. If they were both of the same density, neither would pass through the skin. If the water in the soil were the denser, then the sap would pass out so quickly that the plant would soon be robbed of its water.

“Here are two young plants, each growing in a small pot. I want you to water them, Tom. Water one with salt and water (brine), the other with tap-water.”

Tom did as he was asked.

Plants watered with Fresh and Salt Water.

“See,” said Uncle George, “the one which you watered with brine is drooping. It is bending over the pot. That is because the water outside its root-hairs is denser than that which is inside the plant.”

“How does the water get up from the roots to the leaves?” Frank asked.

“Just in the same way as the oil travels up the wick of the lamp. Water will always travel up through small spaces.”

Uncle George poured some red ink into a saucer, and dipped the corner of a lump of sugar into it. The red ink ran up into the sugar until it was red all over. Next he took a bundle of very small glass tubes, and dipped the ends of them in the ink. The ink ran up the tubes, filling them to the top.

“Inside every plant,” Uncle George went on, “there are thousands of long tiny tubes, up which the water travels. In fact the veins of a leaf are just bundles of tubes, something like the bundle I hold in my hand.”

Questions and Exercises.

1. Why do branches wither quickly when cut from the tree? How would you keep them from withering quickly?

2. Place two small panes of clean glass close together. Dip the corner of them in coloured water, and watch what happens.

3. Why do we never see the silky root-hairs when we dig or pull a plant out of the ground?

III.—THE WEASEL AND THE OTTER.

It was Frank who wanted to follow the stream far up towards the hills. He wished to see where it began, for he had heard that its source was in several small streams many miles away.

Uncle George agreed to take the children as far up the stream as they could walk, without being tired. Soon they were far up above the wood, and the fields, and the pond.

Frank was not in the least sorry when his uncle sat down on a large stone by the side of the stream.

“We shall not go much farther,” said Uncle George. “Some other day we will. But tell me what you think of the country round about you.”

“It is very wild and lonely,” said Tom. “There are no fields of corn; nothing but green hills and moorland. Yet it is very grand.”

“The flowers and plants are not like those of the valley,” said Tom. “The stream, too, is different. Here it is a noisy, rushing course of clear, lovely water. Down below it is a lazy-flowing stream.”

“It is not always so clear,” said Uncle George. “After heavy rains this stream is swollen and brown.”

“Look! look!” cried Dolly. “What is that on the other side of the stream?”

Sure enough there was something moving about. Now it turned round and opened its mouth, showing two rows of sharp, white teeth. Then, with a harsh cry that could be heard above the noise of the water, it bolted away.

There was just time for all to see the creature, which Tom at once called a weasel.

“Yes, a weasel it is,” said Uncle George; “it is one of the animals which prey on rabbits and young hares. Look! there it is again.”

The children looked, and saw it quite clearly. There it was, a pretty little animal of a black and brown colour, with just a little white on its breast. It sat up, and was holding something in its fore paws.

“Ah!” said Uncle George, “our little friend is a thief. He has found a nest, and that is an egg he has stolen from it. Let us see what he will do with it.”

The Weasel at Home.

In a moment or two Master Weasel tucked the egg under his chin and was off once more.

“What a dear little thing, to be sure!”