Background
Jenckes was born on November 2, 1818, in Cumberland, Rhode Island, the son of Thomas B. and Abigail W. (Allen) Jenckes, and a descendant of Joseph Jenks.
Jenckes was born on November 2, 1818, in Cumberland, Rhode Island, the son of Thomas B. and Abigail W. (Allen) Jenckes, and a descendant of Joseph Jenks.
Jenckes was educated at Brown University, from which institution he graduated with distinction at the age of twenty. For one year thereafter he served as a tutor at Brown, meanwhile pursuing the study of law.
Jenckes was admitted to practice in 1840, and having formed a partnership with Edward H. Hazard of Providence, he rose rapidly in his profession. In due course he gave special attention to patent law, a field in which he proved to be peculiarly qualified by his mechanical aptitudes, and was retained as counsel in much of the important patent litigation of his time, including the suits which arose out of the Sickles and Corliss patents relating to the steam-engine and the more famous Day and Goodyear rubber controversies. At an early age he disclosed a flair for politics; he served as one of the secretaries in the "Landholders Convention" of 1841 and in the Rhode Island constitutional convention of 1842. In the same year, 1842, Jenckes was appointed secretary of the governor's council and subsequently did service in both houses of the state legislature. This service led to his election as a member of the national House of Representatives in 1862, and he took his seat at the opening of the Thirty-eighth Congress. He was three times reelected to represent the first Rhode Island congressional district. During his four terms Jenckes served on two important committees - patents and judiciary. His services in connection with the revision and improvement of the laws relating to patents and copyrights were of great and enduring value. He was actively associated with civil-service reform in its earliest stages and indeed he has a fair claim to be ranked as the first American legislator to grasp the significance of this reform. In 1865 he introduced a bill for the selection of public employees by competitive examinations, a measure which he had framed after a study of the English practice and after an elaborate correspondence with Sir Charles Trevelyan and Sir Stafford Northcote, both of whom had played an important part in the English movement for civil-service reform. This bill was defeated, but Jenckes persisted and in 1866 obtained the appointment of a joint committee to study the subject of retrenchment in governmental expenditures. This committee appointed a sub-committee on civil service, with Jenckes at its head, and a bill based on its recommendations was presented to the House in 1868; but this too was defeated, although by a narrow margin. Jenckes was also closely identified with the movement for a national bankruptcy law and was successful in securing the enactment of such a measure after several years of effort. He initiated competitive examinations for admission to West Point. When the impeachment of President Andrew Johnson was voted by the House, his name was proposed as one of the managers to prosecute the impeachment proceedings before the Senate, and he came within a few votes of being chosen. By reason of his independence, integrity, and sound judgment, Jenckes became one of the outstanding members of the Fortieth and Forty-first congresses, becoming widely recognized as one of the best lawyers in the House. Consequently, when it was decided to undertake an investigation of the Credit Mobilier charges against various members of Congress, Jenckes, who was now no longer a member of the House, was selected as one of the counsel to assist in the prosecution of the inquiry. Much was expected of him in this capacity, by reason of his legal talents and high reputation; but ill health prevented him from assuming a leading part in the proceedings. He died on November 4, 1875.
To his contemporaries Jenckes was a somewhat austere figure, aloof and objective, but with intellectual power and legal acumen that commanded the highest respect everywhere. He was always in earnest and rarely lost his temper or self-control.
Jenckes married in 1842 Mary J. Fuller of Attleboro, Massachusetts. They had seven children.