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 handed. Remember this: Left-handed people are just as bright, and just as "handy," or clever, with the hands, as right-handed people. Of course it looks odd to see a person eat and write with the left hand. But "looks" don't count for much when work is to be done. A left-handed pitcher wins many a game of base-ball.

A WHY A POP-GUN POPS
A pop-gun pops from an air explosion. The front end of the gun is made air-tight with a cork or plug. At the other end is the plunger, that fits the round bore just tight enough so it can be forced down to the plug. The bore is, of course, full of air. This air has no chance to get out. So when you push the plunger, the air is squeezed into a smaller space before it. It really becomes compressed air. Air doesn't like being squeezed any more than you do. To get out, it pushes and pushes until the plug gives way. "Pop!" The air instantly expands and sets sound waves in motion. As the act is quick and sharp and short, the sound made by it is also. "Pop!" just describes it. Shut your lips to say "pop." Fill your mouth with air from the lungs. Then let go and speak the word suddenly. In that way you make the same kind of an air explosion as the pop-gun. The power of compressed air is so great that it is used to make drills bore holes in the rocky walls of mines, and to hammer rivets in the iron work of bridges and sky-scrapers. Your pop gun is really a very scientific toy.

HOW CAN A CAT SEE IN THE DARK?
In the first place a cat cannot see in pitch dark. It can only see by less light than you can. You can see in very bright light, and also in dim light. If you come out of a rather dark room where you saw well enough not to bump into things, into strong sunshine, you have to shade your eyes a moment until the pupils become smaller and admit less light. So, in going from brightness to dimness, you can see better after the pupils of the eyes have had time to expand. The eye is a wonderful automatic—or self-regulating—little window. It can shut out light if there is too much, or open up to admit all the possible rays if the light is too dim. The pupils of the cat's eyes are able to close like narrow slits in a shutter, to keep out the noon-glare of the sun; and to expand to a big round window that catches all the rays in semi-darkness. You see cats—lions, tigers, leopards and all the beautiful wild cousins of your playful kitten—are night