when james watt grew up, he was as much interested in steam and its wonderful power, as he had been as a boy. he was sure it could be made of great service to men. it was already used for driving engines, but the engines were not good, and it cost much money to work them. watt thought they could be improved, but it was long before he found out the way to do this. often, he sat by the fire watching the lid of the kettle as it was made to dance by the steam, and thinking of many plans; and at last a happy thought came to him. his plan enabled great improvements to be made in the working of engines, and now steam drives our trains and ships, our mills and factories, and is one of our most useful servants.