It gives heat to the plants in the water, so that they may grow; and it rouses into active life, the fish and other breathing things, from the torpid state in which they are during winter. Does water store away a large amount of heat? It does; and thus the summer is made much cooler. How does water make Autumn warmer? In the autumn the heat in the water is given off, so that the air is kept warmer than it would otherwise be. How does this affect autumn weather? It makes that season of the year mild and pleasant. What advantage is derived from this? It gives the late fruits and seeds a chance to ripen; and it affords time for the sap of plants to return to the roots, and to become prepared for the frosts of winter. How does water make Winter warmer? By being changed into ice and snow. When water is changed into ice or snow, what takes place? The latent heat in the water is given off, and thus the winter air is made warmer. Can water be compressed into a smaller bulk? Yes; it can be compressed, but not so much as air. What is said of water that is compressed? Its particles are pressed closer together, and it is said to be more dense. Why is the water at the bottom of a pond more dense than that at the surface? Because the water at the bottom of the pond has to bear the weight of all the water above it. Is the weight of the water very great? The weight of the water is very great. What is its weight at the depth of one hundred feet? At the depth of one hundred feet, it presses in every direction, with a force of forty-three pounds on every square inch of surface. What is its weight in the ocean at the depth of one mile? At the depth of one mile it presses in every direction, with a force of two thousand three hundred pounds on each square inch of surface. When one opening is made near the top, and another near the bottom of a vessel full of water, from which will the water flow with the most force? From the opening near the bottom of the vessel. Why is this? Because there is more weight of water to press it out from the opening near the bottom. When water is poured into a vessel, what becomes of it? It spreads out so that its surface is level. When different vessels are connected together, what does the water do? It falls to the same level in all of them. How high will the tea stand in the spout of a tea-pot? Just as high as the tea is in the tea-pot. [Illustration: Fig. 20.] Will the tea in the spout balance that in the tea-pot? The tea in the spout will balance that in the tea-pot, as is shown in Fig. 20. How else can it be shown that water will rise to the same level in different vessels? By a reference to Fig. 21, this may be seen. [Illustration: Fig. 21.] Let these vessels be made so as to connect with each other by the tube at the bottom; then, when water is poured into one of them, it will rise up in each of the others, so as to be the same height in all.