“I think a seed is a most wonderful thing,” said Tom. “It is,” said Uncle George, “wonderful indeed. The most wonderful thing about it is that there is life in it—sleeping life, awaiting these three things I have told you about. “Dried up, and as hard as a stone, it will keep for years; but when air, warmth, and moisture are given it, it springs into life and becomes a plant, which grows, produces seeds, and dies. “Now, we will plant the rest of the soaked beans—not in ground, for I want to let you see that the seed-leaves contain far more food than the tiny plant requires to feed it until it is old enough to take care of itself. “We will plant these seeds in damp sawdust, from which they can get no food. We will see that they get water, air, and warmth, but no food except what is in the big seed-leaves.” Uncle George then got a box filled with sawdust, and placed the beans in it. He arranged them in different ways. Some beans he placed edgeways, others longways, others lying on their sides. “I am doing this,” he said, “to show you that, no matter how a seed happens to lie in the soil, its root will always grow down and its shoot will always grow up.” He then covered them up with a thin layer of sawdust, and placed the box in a warm corner of the kitchen. The boys promised to water the seeds every day, and to watch them as they grew. Exercises on Lesson IV. 1. Soak some seeds of broad bean (or pea) and maize (or wheat) for twenty-four hours. Plant some in damp sawdust. 2. What do you see when you open a bean seed? 3. Pick off the little baby plant, and try to draw it big. 4. Cut down through the centre (flat side) of a maize seed. Try to make out the little seed plant and the food store. 5. Every third day dig up a growing seed and draw it. Put the date beneath each drawing. Keep your drawings carefully. V.—HOW A PLANT GROWS. Every day the boys watched their buds and seeds bursting into life. It was slow work; but, as winter passed slowly away and they were able to go out for walks more often, they had much to amuse them. They brought home all sorts of curious things, and soon had quite a host of living things to watch. [Illustration: Four Stages in the opening of Horse-Chestnut Buds.] Three weeks passed before the horse-chestnut buds showed any signs of opening. By this time they had swelled out very much. First the sticky scales moved apart, then folded themselves backwards out of the way, and at last fell off altogether. This moving apart of the scales was caused by the shoot or branch inside the bud, which was growing rapidly. Before the scales fell off, it had burst its way through them. It was now a large mass of thick leaves all folded together, and covered all over with a sort of wool.