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We train horses to draw our wagons. We put windmills. The wind makes them go round and pump water for the cattle to drink.

The sailor places sails upon his vessel and the wind blows him merrily along. The engineer places water in a boiler and heats it until it changes to

steam.

The steam makes the engine move and work for us.

Can you think of any other thing which we harness and cause to work for us?

Long ago people did not know that steam could be made to do work. Then they used water to make their mills go and grind the grain.

Let us look around and see the work which water does. When a raindrop strikes your face it hits a tiny blow. The raindrops which run from the roof dig a little ditch by the side of the house. When thousands of little raindrops meet and travel together they often do a great deal of work. Sometimes we wish that they did not do so much work.

As the raindrops rush along they dig a deep ditch in the soil. They do this by carrying off the dirt, grain by grain. They become very muddy, but they do not seem to care.

Have you ever seen great holes washed in the road by the torrent of raindrops? People cannot travel for a time. It It may take many men several days to fill up the hole made by the torrent.

If you live by a river or mountain brook you have seen the water roll pebbles along. The river sometimes washes away people's houses. It has destroyed whole farms.

The waves of the ocean also do work. They

never become weary. They are tearing the rocks down and grinding them to pieces. They make the sand which you delight to play in.

Sometimes the waves throw great ships against the rocks. They seem to be happy in breaking things in pieces and doing all the harm they can.

How do you suppose men harness the water and make it work? It is a pleasant trip to the old mill.

There we can learn more about the work of water, and how water is harnessed.

The mill stands by a little creek. Above the

mill you will see a pond of water held by a dam. The dam is made by piling logs or rocks across the bed of the stream. The dam holds the water back so that it cannot run along as it used to do.

Upon one side of the mill-pond the miller digs a ditch. At the lower end of the ditch he places a large wooden wheel. This is called a water wheel. When the dam is full of water the miller turns the water into the ditch. The water runs through the

ditch and onto the wheel. The The weight of the water makes the wheel turn around. The wheel makes the mill go to grind the grain or do any other kind of work. The mill may weave cloth. It may make electricity to give us light.

Mills are sometimes placed where there is a water-fall. Then it is not necessary to make a dam.

do.

QUESTIONS.

Mention some of the things which work for us.

Mention some of the kinds of work which you have seen water

What does the river do with the dirt which it washes from its banks?

What kinds of work does the ocean wave de

Describe a stream near your home after a hard rain.

Tell how water makes the water wheel turn around.

How are dams made to hold the water?

What harmful kinds of work does water do?

What makes the water come out of the hydrant with such force? In what kind of a country will water do the most work, a hilly or level one?

Would there be any waterfalls if there were no hills?