The firm of William Sellers & Company had another master mind in that of Dr. Coleman Sellers, a second cousin of William Sellers.[211] He was born in Philadelphia in 1827, his father, Coleman Sellers, being also an inventor and mechanic. Like Nasmyth he spent his school holidays in his father’s shop, which was at Cardington. In 1846, when he was nineteen years old, he went to Cincinnati and worked in the Globe Rolling Mill, operated by his elder brothers, where the first locomotives for the Panama Railroad were built; and in two years he became superintendent. In 1851 he became foreman of the works of James and Jonathan Niles, who were then in Cincinnati and building locomotives. Six years later he returned to Philadelphia, became chief engineer of William Sellers & Company, and remained with them for over thirty years, becoming a partner in 1873. During these years he designed a wide range of machinery, which naturally covered much the same field as that of William Sellers, but his familiarity with locomotive work especially fitted him for the design of railway tools. His designs were original, correct and refined. The Sellers coupling was his invention and he did much to introduce the modern systems of power transmission. [211] See Trans. A. S. M. E., Vol. XXIX, p. 1163; _Cassier’s Magazine_, August, 1903, p. 352; _Journal of the Franklin Institute_, Vol. CXLIX, p. 5. Doctor Sellers was a good physicist, an expert photographer, telegrapher, microscopist, and a professor in the Franklin Institute, his lectures always drawing large audiences. Like William Sellers, he was a member of most of the great engineering and scientific societies, here and abroad; and he was president of the American Society of Mechanical Engineers, of which he was a charter member. He was received with the greatest distinction in his visits to Europe. In 1886 impaired health compelled his relinquishing regular work and he resigned his position of engineer for William Sellers & Company, being succeeded by his son, the present president of the company. His last great work was in connection with the power development of Niagara Falls. He was engineer for the Cataract Construction Company and served on the commission which determined the types of turbines and generators and the methods of power transmission finally adopted. Among the others on this commission were Lord Kelvin, Colonel Turretini, the great Swiss engineer, and Professor Unwin, and its report forms the foundation of modern large hydro-electric work. William Sellers & Company has a unique distinction among the builders of machine tools in having had the leadership of two such men as William and Coleman Sellers.