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 worn down to plains, the sea is smaller, the air lighter. There is less heat and air and water. In order to live there at all, many scientists think the Martians would have to be superior to us. They would have to be better thinkers, and use what they have more intelligently and economically than we do. There are long, straight lines on Mars that some astronomers think are canals, to bring melting snow water from the poles to irrigate dry lands. Such vast engineering works could mean only that the people of Mars must long ago have outgrown wars, and turned to world-wide works of peace. New things are being found out about Mars every year. Some of the children who read this may live to know certainly if this little neighbor of ours is inhabited. If it is, then the Martians, too, may be wondering, and even trying to discover, if our earth is peopled.

WHY LIGHTNING RODS PROTECT HOUSES
In the first place a lightning rod does not protect a house unless the lower end is well buried in the ground. If the lower part of the rod is rusted and broken off at the ground it really attracts the lightning, and then discharges it into the house. Lightning is electricity. Metals attract and conduct, or carry electricity better than anything else does. So if lightning is discharged above a house it is easier for it to go to the metal rod and run down that, than it is to spread over the roof. But there is now less faith in the protective powers of a lightning rod than there once was, and fewer rods are used.

WHY A DOG TURNS AROUND BEFORE LYING DOWN
Dogs are wild animals that have been tamed. They have been tamed for so many hundreds of years that they are very different from any and all of their wild brothers of today—wolves, foxes, bears, jackals, and the wild dogs of the Esquimo tribes and of the Bushmen of Australia. But dogs have certain habits to which they cling, that came down from the wild dogs of many hundreds of years ago. One of these habits is the burying of bones. Another is this turning around and around before lying down. Wild dogs had to bury the bones they could not make use of at the time, to keep other A dogs from carrying them away. And they had to make their beds in jungle grass or drifted leaves. This turning trampled a space flat for a comfortable bed, and left a wall of standing grass around it that hid the bed from prowlers. So today, you will see petted house dogs of high and long breed, burying bones stealthily, and turning