Whitworth foresaw that if industrial enterprise would prosper it must be systematized, and workmen must install harmony in their designs, and must aim at minute exactness in their forms and measurements. His attention was particularly directed to the inconveniences which were produced by the variations in the pitch and thread of the screws used in the construction of machinery—variations so considerable, if we may quote the words of an English sketch of his work, "that every maker had screws of his own special sizes, and that the failure of a single one might cripple a machine in a distant country until the original maker could be communicated with and could send out another of the same proportions. Mr. Whitworth not only saw the immense advantages which would arise from rendering the pitch and thread of screws uniform, but also the difficulty which might be experienced in inducing any maker to adopt the proportions used by any other. With rare sagacity, he obtained specimens of all the screws used by leading manufacturers, and then designed one which was the average of them all, and a copy of none. By this expedient he evaded opposition, and worked a revolution in the construction of machinery. The new screw was universally adopted; and, in the present day, every screw of the same diameter has a thread of the same pitch and of the same number of turns to the inch, and all screws of the same size, from whatever maker obtained, are interchangeable."
Mr. Whitworth next took up appliances for accurate measurements, and constructed an instrument capable of measuring the millionth part of an inch, and which, worked by touch, "was so delicate as instantly to communicate the expansion of a steel bar three feet in length when this was warmed by momentary contact with a finger-nail." With these and his other inventions, "Whitworth's standard gauges, his taps and dies, his uniform system of screw-threads, his great refinements in the manufacture of lathes, planing-machines, drills, etc., all became available at the moment when they had become indispensable, . . . if the imperative demands for mechanical appliances in every direction were to be worthily met."
In 1853 Mr. Whitworth was appointed a commissioner to the great exhibition in New York, and in that capacity wrote a report on American manufacturing industries which attracted much attention at the time, and still has interest. In the next year he was requested by the British Government to design and produce machinery for the manufacture of rifles for the army. He found it with the rifles as it was with nearly all mechanical appliances before he touched them to improve them—no two of them were alike. He imposed as a condition of his accepting the commission that he should be permitted to determine what form and dimensions of guns and bullets would produce the best results. Besides consenting to this condition, the Government erected a shooting-gallery five hundred yards long on Mr. Whitworth's grounds at Rusholme, where he was able to devote himself to most careful and thorough ex-
