Chamberss Elementary Science Readers | Page 5

rows and rows of slates.'
2. Out they ran, looked all over the ground, then at the garden-wall, then back at their mother, who had come to the door.
'Look at the house,' she said, 'look higher!'
3. 'Oh, we never thought of the roof,' they cried, and ran in again laughing. 'But those slates are not so nice and smooth as our slates.'
'Your slates are made smooth on purpose. Besides, they are made of better slate--older slate. The older the slate is the better it is.'
4. 'How old?'
'No one knows. It is a long story, and no one can tell it properly. Shall I tell you as much as I know?'
'Yes, do, please, mother!' and the two settled themselves at her feet.
5. 'Well,' she began, 'once upon a time there was a great stir at the bottom of the sea. The heat and gas under the ground broke through and pushed out everything that was in the way.
6. 'Stones, ashes, and dust came flying up through the water, and then fell back into the water again. When all was quiet, they settled down at the bottom of the sea, and became mud.
7. 'All this happened many times, till there was a great deal of mud. Then, little by little, the mud was covered up by other things.'
8. 'What sort of things?'
'Dead fish, perhaps, and shells, and sand and mud that had been brought by rivers into the sea. These things lay on the top of the mud and weighed it down.
9. 'The heat under the bottom of the sea still kept up, and made the mud very hot, and baked it through. At last it gave a great push, and heaved the mud up above the water, so that it became dry land.
10. 'In other ways it was made harder and harder, until it was turned into rock. And now we call it slate. Here is a bit of your old broken slate. See if you can turn it into mud again!'

CHALK.
PART 1.
a-cross′ morn′-ing chalk′-ing picked piece teach′-er black′-board spread′-ing wheat col′-ours fetch laughed earth brown moist through
1. A few days after this, Dora and Harry were going across the fields. They saw a horse and cart standing, and a man taking white stones out of the cart and putting them over the ground.
2. 'Why, it is Joe!' they cried, as they came nearer. 'Good-morning, Joe. What are you doing?'
'Chalking this bit of land, you see. You know what chalk is, do you?'
3. Harry and Dora picked up a piece or two.
'Teacher writes on the blackboard with chalk,' they said.
'Yes, you are right. It is used for many things,' and he went on spreading it over the field.
4. 'But what is it wanted here for, Joe?'
'No chalk, no wheat!' said Joe.
'Father put no chalk on our field, and we had such a heap of wheat!'
5. 'Yours is good land. This up here has never been used for farming. It had little old trees on it, you know, and they were cut down and their roots dug out of the ground; and now, look at it! It is poor soil.'
6. 'How do you know it is poor?'
'Look at the field below, what a nice brown it is! That will grow anything, but this is all colours--black, red, yellow, and green.
7. 'I have been a long way to fetch this chalk: I started off with old Dobbin this morning before it was light, and got it out of the chalk-pit.'
8. 'When we were fast asleep!' said Dora.
'Then you don't buy chalk at a shop?' said Harry.
Joe laughed.
'No; it comes out of the ground.'
'This is like the slate story,' said Dora.
Harry nodded.
9. 'But, Joe, I want to know how the chalk makes the ground good.'
'I don't know how, but it does. If it lies here for a year or more, the earth will turn brown, and we can grow wheat in it. Besides, chalk holds water, and so it will keep the ground moist up here.'
10. 'How?'
'Well, when it rains, the water will not run away through the earth, but will stay in the lumps of chalk. Are you going? Good-bye, then.'

CHALK.
PART 2.
[Illustration: 'Fizz and bubble, bubble and fizz.']
eve′-ning brought vin′-e-gar bub′-ble air stirred poured grains hun′-dreds smiled crowds threads catch died dropped mixed
1. The children had much to say that evening about Joe and the field. They had brought home a lump of chalk.
2. 'I will show you something,' said father, and he got a cup of vinegar, crushed a little of the chalk, and dropped it into the cup.
Fizz and bubble, bubble and fizz!
3. What was going on?
When the stir came to an end, the chalk was not there!
'Part of it has gone off in gas,' their father said. 'The rest is lime, and it is mixed with the vinegar.'
4. 'We did not