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"That is Lookout Mountain, and to the left is the lower part, known as Missionary Ridge. Have you ever heard of these places before?"

"Why, yes. It was on Lookout Mountain that the 'Battle above the clouds' was fought under Grant, and Missionary Ridge was taken by Sherman the next day." "We will go up there before we leave."

They did so, and found still left some reminders of the terrible battles; the magnificent view from the highest peak, sixteen hundred feet above the Tennessee, rewarded them fully for their visit. George made a sketch of the town, river, valley, and hills, similar to the picture which is given on page 49.

On the following day Mr. Cartmell passed in the forenoon up the beautiful East Tennessee valley, and then on to Cincinnati and Pittsburg.

LESSON V.

IRON FURNACES.

"WHAT do you wish to see to-morrow, George?" asked Mr. Cartmell.

"I would like to see how iron is made."

"What do you wish to see, Fred?"

"I want to see the oil fields."

"The iron-mills are near us in the city, so I think we will visit them first. So much iron is found in this part of Pennsylvania, and is here produced in such quantities, that this city is often called the Iron City.' Is iron found in other places?"

"It is found," George replied, "in several of the southern and western States. I think the Lake Superior mines, in Michigan and Wisconsin, are the richest in the country. There are also valuable mines in Canada."

"Iron is combined with many other substances in the earth, and in this form it is called iron ore. The iron in the ore is usually separated from the impurities by great heat in a blast-furnace.

"The blast-furnaces in which this is done look like chimneys from forty to one hundred feet in height. At the base these furnaces are square, and have openings on each side, so that the melted iron and slag may be drawn off, and the blast admitted."

What do you mean by the blast?"

"The current of air that is furnished to make the fire burn more freely. We do just the same thing when we use the bellows to make the fire on the hearth blaze more brightly."

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"Do they use bellows in these furnaces?" asked Fred. "There are great blowing-engines which force the air into reservoirs, and from these it is carried to the furnace by means of pipes. This air is heated before it comes here, so that it does n't cool either the ore or the coal."

"Does each furnace have its own blowing-engine, or can several of them be supplied with air by the same engine?"

"Sometimes as many as a dozen furnaces are built together, and the same engine supplies them all with air."

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The next day Mr. Cartmell, Miss Gray, and the children visited some of the noted iron-works in Pittsburg, and studied the process of making iron and steel.

At the first iron-mill they saw a man charge a furnace. He opened a door near the top of the furnace and dumped in a wheelbarrowful of coal; then he put in iron ore; then some limestone, so as to make layers of each kind. As soon as the right amount of matter had been thrown

in, the workman closed the door, and looked toward the children, and said a pleasant word to Nellie and Florence.

"If you are trying to purify the iron, why do you put limestone with it?" asked Florence.

"Iron melts more quickly when the limestone is used. Then, too, it carries off some impurities with it. On account of its weight the iron sinks to the bottom of the furnace, and then is drawn off."

"Does it take long to melt?" inquired Miss Gray.

"It is generally drawn off twice a day, — in the morning and again at night. They will draw off about four o'clock this afternoon."

Mr. Cartmell and the others came back to the building at the appointed time to see the furnace tapped. As soon as the opening was made, the melted iron ran out, looking like liquid fire, shooting forth in all directions showers of sparks, and driving the girls and Miss Gray back to a safe distance. The heat was intense.

The melted iron ran down the large trench, and into the side-trenches where not stopped by the workmen, and from the side-trenches into the short openings in the sand. It soon cooled and hardened. Then the men broke the short pieces, or "pigs," from the longer ones, which are called by them "sows; " hence this form of iron is called "pig-iron," or cast iron. In this form it is sent from Pittsburg to many other places, and used for stoves, and ten thousand other useful things that can be made by simply melting and recasting.

"You have all seen," said Miss Gray, " many beautiful and sometimes delicate things that are made out of iron by recasting, as they made the scales in Vermont. You remember, too, how brittle such things are, and how often they are broken."

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