There came then into Watt's mind the idea of an engine that would produce _rotary_ motion. This he patented in 1781. All round and about, ready to pounce on it, were a perfect swarm of pirates.
"One's thoughts seem to be stolen before one speaks them," he said. And again, "All mankind seem to be resolved to rob us."
In 1782 the first rotary machine worked. After long waiting there was a brilliant result. It was made to drive a corn-mill. In our day it would be hard to say what Watt's rotary machine is not made to do. It is made for corn-mills and for cotton-mills, for sugar-mills and iron-mills. It drives our steamers and rolls our hammer-iron and coins our money and prints our books.
And now the great inventor had reached the highest pinnacle of fame. In 1790 he had an interview with the King, who asked about his engines.
But he had not landed at the topmost round of the ladder without much painful climbing and many weary steps. His life had been all through shadowed by ill-health, and an anxious, worrying mind that refused to be calm. He had a shrinking distaste to business, and a fearful habit of looking on the dark side of things. Often would he have sunk in depression and despair had it not been for his cheery partner. It was only in the late years of his life that he came to know anything like peace. His mind all along had been too active for his body.
But though as an old man he retired from public life and from business, he could not altogether retire from invention. He invented a letter-copying machine, and one for copying statuary. In his old age he lived very quietly in his comfortable house near Birmingham, furnishing what he called his Garret, a room where he might be alone and still invent, don again, as in boyhood, the leather apron, cook his own food, and ponder anew the details of those wonderful inventions he had given to the world.
Friends admitted there found "the great Mr. Watt" simple, modest, careless of display--much as he had been as a boy--his voice low and kindly, with still its broad, homely Scottish accent. The world would have liked to draw him from his seclusion, to caress him, to make much of him. It offered him a baronetcy, but his simple tastes lay not at all in the direction of such honours, and he refused it.