862 WILLIAM SELLERS. 



Probably the best known of his achieAements in this field is the spiral 

 gear planer drive, in which the table is moved back and forth by a 

 multi-thread screw engaging with a rack on the under surface of the 



table. 



In 1868 Mr. Sellers formed the Edgemoor Iron Company which 

 furnished the structural material for the Centennial Exhibition build- 

 ings of 1876, in Philadelphia and the structural material for the first 

 bridge between New York and Brooklyn. 



In 1873 he reorganized the Midvale Steel Company at Nicetown 

 near Philadelphia which, under his management entered the field of 

 producing material for steel cannon for the Government. 



In 1860 Mr. Sellers had his attention directed to the GifFord injector 

 for feeding hot water to steam boilers. He commenced the manufac- 

 ture of injectors under this design, but in 1865 invented and patented 

 the self-adjusting combining tube, which automatically adjusted the 

 supply of water to the apparatus to meet the varying requirements 

 as the steam pressure in the boiler might vary. These injectors were 

 made in the Sellers shop by metric sizes and with the special gages 

 which the use of this unusual standard compelled. Further develop- 

 ments led to more advanced and larger sizes of injectors, particularly 

 for locomotive service. 



The Navy Department at Washington sent out specifications for 

 a turning and boring lathe in 1890 for its 16" steel cannon. The 

 bed was to be 73 feet long with an extension of 53 feet for the bor- 

 ing arrangement. Mr. Sellers made a complete new design which 

 he considered superior to that offered by the Governmental Depart- 

 ments and with the co-operation of a special commission created in the 

 American Society of Mechanical Engineers, at the request of the Navy 

 Department and of which the late Professor John F. Sweet was an 

 active member, the Sellers design was accepted and the Navy design 

 was discarded. This lathe weighed more than 250 tons. 



The Sellers firm is also identified with the formulation, through the 

 Franklin Institute, of a system of standard screw threads which 

 became known as the United States standard and was presented to the 

 Institute at a meeting on September 16, 1864. 



Mr. Sellers received about 90 U. S. patents, the earliest one in 1857 

 and some were pending at the time of his death — January 24, 1905, 

 in the 81st year of his age. ' 



Mr. Sellers received many honors in the field of applied sciences. 

 He became a member of the Philosophical Society in 1864, and of the 

 American Acadeni\- of Arts and Sciences in 1875. He was a member 



