পাতা:পদার্থবিদ্যাসার.djvu/৬৯

58 are called. The water is evaporated, and the salt is left behind. Pup. How beneficial is the sea for mam ! Tut. But surely you have not forgotten the great benefit man receives from that vast inexhaustible store of fish which it contains, great and small, from the whale even to the shrimp; for even those which are not good for food are useful for the wants and conveniences of life. Neither have you forgotten the extensive and general benefits of commercial intercourse, carried on upsly its surface, between the most distant nations of the earth; the support which it is the uleans of affording to ship-builders, and to so useful a body of the community as sailors. Pup. What contines and keeps the sea within its proper bounds? Tut. The divine appointment. God has said to the raging sea, “ Hitherto shali thou come, but no farther: and here shall thy proud waves be staid.” Pup. What an immense quantity of vapour must be raised out of the sea, to supply the springs which form so many great rivers in every quarter of the world ! But how is water raised into the air, which I have heard you say is much heavier * Tut. This merits your attention. Though water is, as you remember I told you, heavier than air, yet it is . capable of being made lighter than air, and then it will ascend. The water which you see on the kitchen fire, would all evaporate in steam when boiling. This familiar occurrence may serve to give you some idea how water may be made to ascend in the air. Our philosophers tell us, that a particle of water may be so rare.