Passing over some minor attempts, the next great development was that of Allen Wilson, who, without having heard either of Howe's or of any other machine, constructed one in 1849, the design of which, he said, he had been meditating for two years. His first machine had original features, however much it may have been anticipated in principle by Howe's patent. In Wilson's second design, a rotary hook was substituted for a two-pointed shuttle, and by other improvements he achieved a greater speed than had been attained by other inventors. Later still, he added the 'four-motion feed,' which is adopted on most of the machines now in general use. This idea was an elaboration of a principle which seems to have first occurred to the unfortunate Morey. In Morey's machine there was a horizontal bar with short teeth, which caught the fabric and dragged it forward as the stitches were completed. It took nearly thirty years, however, to evolve the perfect 'feed' motion out of Morey's first crude germ. While Wilson was working away, perfecting his now famous machine, an observing and thoughtful young millwright was employed in a New York factory. One day a sewing-machine was sent in for repairs, and after examining its mechanism, this young man, whose name was Isaac Singer, confidently expressed his belief that he could make a better one. He did not propose either to appropriate or abandon the principle, but to improve upon it. Instead of a curved needle, as in Howe's and Wilson's machines, he adopted a straight one, and gave it a perpendicular instead of a curvular motion. And for propelling the fabric he introduced a wheel, instead of the toothed bar of the Morey design. It need hardly be said that the Singer machine is now one of the most widely known, and is turned out in countless numbers in enormous factories on both sides of the Atlantic. It is not so well known, perhaps, that Singer, who was a humble millwright in 1850, and who died in 1875, left an estate valued at three millions sterling--all amassed in less than twenty-five years! The machines of Howe, Wilson, and Singer were on the lock-stitch principle, and the next novelty was the invention of Grover and Baker, who brought out a machine working with two needles and two continuous threads. After this came the Gibbs machine, the story of which may be briefly told.