UNTIL a little more than one hundred years ago, the chief power used in the production of food, clothing, and shelter was hand power. Cattle and horses were used to cultivate the fields. Windmills and water wheels were employed to grind corn and wheat. But most tools and machines were worked by hand. Men had, for many years, dreamed of a new power which would be more useful than either work animals, sails, windmills, or water wheels. This new power was steam. Yet no one had been able to apply the power of steam so that it would grind corn and wheat, spin and weave cotton and wool, or do any useful thing at all. The man who succeeded in giving to the world this new power was James Watt. Steam now propels ships over the Atlantic in less than a week. It speeds express trains across our continent in ninety hours, and it does a thousand other wonderful and useful things.