"What are they for?" asked the boy, immediately all interest, for he was a member of the metalworking class in his school, and was constantly on the lookout for better ways of working in iron, steel, copper, and brass. [Illustration: THERMIT IN ERUPTION With a blinding, dazzling glare and a gentle hissing the thermit in a white-hot molten mass fills the mould and runs down the sides like volcanic lava.] [Illustration: DR. HANS GOLDSCHMIDT The inventor of Thermit.] "Well, they both are used in welding metals and in one--the thermit process--the hardest steel can be reduced to a molten mass of white hot metal boiling like a tea kettle on a stove, in about a half a minute. You see that requires a great deal of heat," continued the chemist, "and in fact the temperature is 5,400 degrees, Fahrenheit. "The other process that I have been trying is known as autogenous welding, and in this even a greater temperature is generated than by the thermit process. In the tiny flame no bigger than the point of this pencil that comes from the autogenous welding torch the temperature is about 6,000 degrees Fahrenheit." "My!" said the boy, "how could any one ever measure such a heat as that?" "Science teaches us how to do that just as science taught us how to produce these great heats. Why, you know, in the electrical furnaces at Niagara Falls they produce a heat that they think reaches the 10,000 degrees of the sun. Outside of that, however, the thermit process and the autogenous welding process attain the greatest known heats." "Those must be fine," said the boy, "because before our schools began to teach metal working, I used to play blacksmith and heat pieces of iron in the fire, but I could never do anything with it, and now that we are learning welding in the blacksmith shop at school I see what a hard job it is. I wish we could use these processes at school." "Well, you will be able to use them some day," said the scientist, "but it took science a long time to find out how to produce and use very high temperatures. "In the stone age, thousands and thousands of years ago, when men lived in caves and ate raw the animals that they caught with their hands, fire was first discovered by an accident. There are many legends of how the hairy savages that populated the earth fell down and worshipped the aboriginal scientist who taught them how to warm their caves.