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Rh ous thirty years ago as a necessary equipment in all up-to-date machinery, and it would be rather interesting to know how many of the thousands of machinists who used them daily had any idea then that they were the invention of a colored man.”

Another great Negro inventor was Granville T. Woods who patented more than fifty devices relating to electricity. Many of his patents were assigned to the General Electric Company of New York, the Westinghouse Company of Pennsylvania, the American Bell Telephone Company of Boston and the American Engineering Company of New York. His work and that of his brother Liates Wood has been favorably mentioned in technical and scientific journals.

J. H. Dickinson and his son S. L. Dickinson of New Jersey have been granted more than 12 patents for devices connected with player pianos. W. B. Purvis of Philadelphia was an early inventor of machinery for making paper bags. Many of his patents were sold to the Union Paper Bag Company of New York.

Today the Negro is an economic factor in the United States to a degree realized by few. His occupations were thus grouped in 1920: