Morris Longstreth Keen was born on May 24, 1820 in Philadelphia, Pennsylvania, United States, the son of Joseph Swift and Ann (Longstreth) Keen. He was descended from Joran Kyn, a soldier who accompanied Governor Johann Printz from Sweden to the Swedish colony on the Delaware River near Chester, Pennsylvania, in 1643.
Keen received his early education in private schools in Philadelphia and subsequently entered the shops of the Norris Locomotive Works there as an apprentice machinist. He also learned pattern making and iron foundry work.
Keen organized with his brother Joseph a manufacturing business, specializing in the making of flat-irons. The design of these irons was based upon an invention which Keen patented in the early fifties. More interested in the development of new ideas than in business, he turned his attention toward improvements in paper manufacture. Many attempts to produce a pulp out of the softer kinds of wood had been made and many patents had been issued for such processes, both in Europe and in America. It was not until 1854, however, that a practicable chemical wood-pulp patent was secured by Watt and Burgess of London. The process, in a crude form, was the soda pulp process still extensively used. For three or four years Keen conducted experiments in the design of wood-pulp boilers. He continued this work at Royers' Ford, outside of Philadelphia, where Hugh Burgess, one of the co-patentees of the soda process in London, settled in 1855.
By 1858 Keen had advanced with his experiments so far that he believed he possessed improvements over the Watt and Burgess basic invention, and after securing the financial aid of William F. Ladd he obtained an assignment of the Watt and Burgess patent. With the American rights to this basic patent he then continued his experimental work and on September 13, 1859, secured his first paper-making patent, on a boiler for making paper pulp from poplar wood. Burgess then joined Keen, and the two began to make wood-pulp paper at Royer's Ford. In 1863 they formed the American Wood Paper Company at Manayunk, Pennsylvania, near Philadelphia, and in the succeeding years produced a considerable quantity of pulp.
In 1863 also Keen obtained an improvement on his pulp boiler, and in 1865 he was granted with Burgess a joint patent for an apparatus to evaporate and calcine alkaline solutions. About 1870 Keen transferred his work to Jersey City, New Jersey. There between 1870 and 1873 he secured three patents on the manufacture of paper stock, which were assigned to Samuel A. Walsh of Jersey City. Subsequently, Keen went to Stroudsburg, Pennsylvania, and on a site between Stroudsburg and the Delaware Water Gap established what he called "The Experiment Mills. " Here he continued his research work in paper manufacture and obtained several additional patents. One of these, a reissue on the process and apparatus for evaporating and calcining alkaline solutions, was granted January 30, 1877, and assigned to the American Wood Paper Company. His last patent on paper making, No. 240, 318, was obtained April 19, 1881, two years before his death.
Keen was unmarried.
