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John Chipman Hoadley
"MR. JOHN CHIPMAN HOADLEY.
On the 21st of October, death brought to a close the career of John Chipman Hoadley, of Boston, U.S., an American engineer whose breadth of attainments rendered him one of the leading men in the profession, especially in steam engineering, in which he was an authority equalled by few.
He was born in the State of New York in 1818, and his first engineering experience was in connection with the system of State canals, which was founded by the Dutch settlers in the seventeenth century, and increased from time to time as the needs of the day demanded. Leaving the State Engineers Corps at the age of twenty-six, he became engineer for the construction and equipment of a number of mills at Clinton, Massachusetts, devoting himself to the wide range of work necessary to build up a variety of industries, a task which could not be accomplished, except by one possessed of unusual force, skill, and versatility.
Later he became manager of a large machine shop in Lawrence, and for a number of years was engaged in the manufacture of locomotives and textile machinery. His experience with locomotives led him into an analysis of the dynamical relations which speed bore tothe operation of engines ; and the result of his investigations, partly mathematical and partly experimental, resulted in the invention of the Hoadley portable engine, which was probably the first application of scientific principles to the design of high-speed engines. These engines contained numerous radical features, since appropriated by others, notably the application of an automatic variable cut-off to a single slide valve, operated by a governor attached to the side of the driving pulley of the engine. We do not speak by the letter as to the exact limitations of Mr. Hoadley ’a inventions in this respect, as measured by the patents issued to him, but the fact remains that he was the pioneer in the successful application of the methods of construction of the Hoadley engine, which were manufactured in great numbers for many years.
During the later years of his life he separated from commercial and manufacturing affairs, and confined his attention to the practice of his profession in consulting engineering and as an expert in patent causes. In this latter capacity his services were held in highest repute, his retentive memory rendering an extended reading and wide experience tributary to a power of keen analysis which would set forth the measure of each patent’s merits, or the worth of the mechanical features of an invention.
His acquirements were not limited to technical matters, but extended through a wide range of general culture. The transactions of the American engineering and scientific societies contain frequent contributions from his pen ; the members of the British Association may recall among these his paper on “ American Steam Engine Practice in 1884,” read at the Montreal meeting, and which was the first step in the recent polemical engineering papers respecting English and American railway practice.
Mr. Hoadley was always interested in public affairs, but he held few offices. He was, however, the engineer member of the Board of Health of the State of Massachusetts. He also visited England and the Continent in 1862, on the part of the State Government, making an examination of fortifications for the purpose of devising a system for American sea coast defences.
The professional work of Mr. Hoadley is shown by its influence over a wide range of engineering practice in millwork, applications of steam, sanitary engineering, and methods of expert evidence, rather than in any massive structures which bear his name as builder. In his personal address, he was especially genial, and endeared himself to a large number of friends."