GRAFF, Frederick, engineer, born in Philadelphia, Pit., 27 August, 1775; died there 13 April, 1847. His early life was devoted to the trade of a carpenter, and he acquired skill as a draughtsman. When twenty years old he met with an accident, and was employed by H. B. Latrobe, as his assistant engineer, in erecting the first water-works in Philadelphia, which were in Centre square, the site of the present city-hall. On 1 April, 1805, he was elected superintendent and engineer of the works. These were found to be wholly inadequate after several years of trial, and in 1811 he recommended Fairmount as the proper place for the water-works, and was intrusted with their construction. At this time the pipes were made of wood, but he devised the iron-pipe system which is now universally used. He brought the work to perfection, and patterns of his fire-plugs and stop-cocks were sent to England. His experience and ability now became acknowledged throughout the country, and he supplied detailed information to about thirty-seven corporations in the United States, including New York and Boston. He was engaged for forty-two years in the service of the City of Philadelphia, and a monument to his memory is erected in the grounds at Fairmount water-works. In 1822 the City water committee sent him a resolution of thanks, and he was presented with a silver vase. In 1828 he received another from the water committee "as a testimonial of respect for his talents and zeal effectually displayed in overcoming an-foreseen difficulties encountered in the construction of the northeast reservoir at Fairmount."