Q. _Why are there WAVES in the sea?_ A. The wind (acting on the surface of the sea) _piles up ridges of water_, which leave behind an _indentation_: as the water on all sides rushes to _fill up this indentation_, the disturbance spreads on all sides, and billow rolls after billow. Q. _Why does WIND in England generally feel COLD?_ A. Because a _constantly changing surface_ comes in contact with our body, to draw off its heat. Q. _Why is a ROOM (even without a fire) generally WARMER than the OPEN AIR?_ A. As the air in a room is _not subject to much change_, it soon becomes of the same temperature as our skin, and no longer feels cold. Q. _Why do we generally feel COLDER out-of-doors?_ A. Because the air (which surrounds us) _is always changing_; and as fast as _one_ portion of air has become warmer by contact with our body, _another colder portion_ surrounds us to absorb more heat. Q. _Why are HOT FOODS made COOL by BLOWING them?_ A. Blowing causes the air (which covers the hot food) _to change more rapidly_; in consequence of which, the hot air is _quickly blown away_, and gives place to fresh _cold air_. Q. _Why do ladies FAN THEMSELVES in hot weather?_ A. By the action of the fan, _fresh particles of air_ are perpetually brought in contact with the face, and every fresh particle of air _absorbs some heat_ from the skin. Q. _Does the fan COOL the AIR?_ A. No; it makes the _air hotter_, by imparting to it the heat _out of our face_: but it cools the _face_ blown upon, by transferring its heat to the _air_. Q. _Is the AIR in SUMMER time ever so hot as our bodies?_ A. No, not in England. In the hottest day in summer, the air of England is 15 or 20 degrees cooler than the human body. Q. _How fast does wind travel?_ A. A gentle breeze goes at about the rate of 5 miles an hour. A high wind from 20 to 60. A hurricane from 80 to 100 miles an hour. Q. _How is the VELOCITY of WINDS ascertained?_ A. By observing the velocity of the clouds, and by an instrument for the purpose. This instrument is called an ANEMOMETER. Q. _How is the VELOCITY of the CLOUDS ascertained?_ A. By observing the speed of their shadow along the ground; which is found in a high wind to vary from 20 to 60 miles an hour. Q. _Why is there always a strong DRAUGHT through the KEYHOLE of a door?_ A. As the air of the room we occupy is _warmer than the air in the hall_, therefore the cold hall air _rushes through the keyhole_ into the room, and causes a draught. Q. _Why is there always a strong DRAUGHT UNDER the DOOR, and through the crevice on each side?_ A. The cold air _rushes from the hall_ under the door, &c. into the room, to supply the _void_ caused in the room (by the escape of warm air up the chimney, &c.) Q. _Why is there always a DRAUGHT through the WINDOW crevices?_