JOSEPH HENRY - AUTOGRAPH LETTER SIGNED 02/08/1866 CO-SIGNED BY: DONALD MacLEOD - HFSID 17974

JOSEPH HENRY and DONALD MAC LEOD
Joseph Henry forwards a letter and enclosures for Donald MacLeod.
Autograph Letter signed: "J. Henry", 1p, 5x8. Smithsonian Institution (Washington, D.C.), 1866 July 8. To Professor Henry D Rogers, no place. In full: "This and the accompanying letter were received by the mail of this morning. I enclose them in an envelope addressed to your brother Robert. The writer is a gentleman in the Treasury Department, who has resided many years in this city and is apparently quite a favorite with the inhabitants, on account of his social and literary character. Truly yours Sir". Slightly soiled. Slightly irregular right edge. Vertical fold crosses "J" of signature. Overall, fine condition. Henry's letter is written on verso of an Autograph letter signed "Donald MacLeod", Comptroller's Office, February 7, n.y, addressed to "My Dear Sir". In full: "I am very anxious to see Professor Rogers of Glasgow, who is well known to my relatives in Scotland. Not knowing his address I have to beg you to send the enclosed to him, as soon as convenient. Pray excuse this trouble and usage. Yours faithfully." Ink from verso shows through lightly. Otherwise, fine condition. Joseph HENRY (1797-1878), a physicist and scientific administrator, discovered electromagnetic induction and self-induction. He is also credited with the invention of the electric motor (1829) and later invented low-resistance and high-resistance galvanometers. In 1893, his name was given to the standard electrical unit of inductive resistance, the henry. In 1846, Henry became the first Secretary of the newly organized Smithsonian Institution, where he established a continuing tradition of research. Under his leadership, weather reporting stations were connected by telegraph in the U.S. In the spring of 1863, Henry was one of the founding members of the National Academy of Science and served as Academy President from 1867. He was both President of the National Academy of Science and Secretary of the Smithsonian Institution until his death. Donald MAC LEOD (1809-1869), a Virginia native, was a clerk in the Comptroller's Office of the U.S. Treasury Department. An interesting Civil War diary kept by MacLeod during late 1862 is in the MacLeod family papers collection of the Virginia Historical Society. Two items on one sheet.