Joseph Henry: The Rise of an American Scientist

  • Albert E. Moyer
Smithsonian Institution Press: 1998. Pp.348 $45, £34.95

One of the main research problems for nineteenth century physicists was the interconversion of electricity and magnetism, and not only from a purely theoretical viewpoint. The practical applications that were to emerge — the dynamo, the electromagnetic telegraph and the transformer — influenced the lives of everyone, not just the researcher in his laboratory.

Of the many familiar names associated with this subject, first and foremost is the incomparable Michael Faraday (1791-1867) of the Royal Institution in London, a man from a poor family, largely self-educated, mathematically illiterate but clear-thinking and imaginative. Hermann von Helmholtz said of him: “Faraday performed in his brain the work of a great mathematician without using a single mathematical formula.”

However, during the same period, in the fledgling United States, another scientist paralleled Faraday's work in electromagnetism but, aulthough eulogized by the US population at his death, is now nearly forgotten. Joseph Henry (1797-1878), both in his background and his career, was uncannily similar to Faraday.

Henry was born into a Scots Presbyterian family of little means, and what formal education he managed to acquire at the small Albany Academy in New York State was paid for by dint of his own labours. He held strong religious beliefs and through most of his research career was well removed from politics of any sort. During his years as a teacher at Albany Academy, and later as professor of natural philosophy at Princeton (then the University of New Jersey), Henry built electromagnets of great strength, generated electric currents from changing magnetic fields, discovered mutual induction and self-induction, and built a working electromagnetic telegraph, all activities engaged in by his counterpart at the Royal Institution during the same period.

But Henry differed from Faraday in many particulars. He was not blessed with a mentor of the quality of Sir Humphry Davy, nor did he have the financial support that Faraday received from the Royal Institution. As a scientist in the distant former colonies, Henry was isolated from the kind of interaction that Faraday had with his numerous friends and colleagues in the European scientific community. Most important, whereas Faraday's maxim was “work, finish, publish”, Henry was slow to finish and publish his research, perhaps because of pressures of his heavy teaching responsibility, but certainly also in no small part owing to his own inertia. And herein lies the principal reason for his relative lack of credit for what were often simultaneous discoveries.

Albert E. Moyer has produced a fascinating private and public picture of Henry, based in large measure on the archives held at the Smithsonian Institution in Washington DC. The great wealth of material available — including laboratory notebooks, students' comments on his lectures, and private letters — is skilfully interwoven with descriptions of Henry's experimental activities, family life and public contacts. Moyer draws an intimate picture of a Janus-like character.

The public face was described by Spencer Fullerton Baird, his assistant and successor as director of the Smithsonian, in a biographical sketch written for the Encyclopaedia Britannica: “He was a man of varied culture, of large breadth and liberality of views, of generous impulses, of great gentleness and courtesy of manner, combined with equal firmness of purpose and energy of action.” Many of his contemporaries thought Henry to be modest and self-effacing.

Privately, however, a different picture emerges of a man often far from modest in his own estimation and tortured by his perceived lack of appropriate recognition by the scientific community; of an individual with little ability to judge his own work objectively. Henry wrote an anonymous biography of himself for the Princeton Review which dwelt at length on his many accomplishments, including a list of his 22 most significant research projects and discoveries, including the first electromagnets powerful enough to lift more than a ton, the first continuously operating machine based on an electromagnet, the development of the concept and apparatus essential for electromagnetic telegraphy and the discovery of self-induction.

Another anonymous article appeared in the Encyclopedia Americana reviewing the advances in electricity and magnetism before 1847 in which he elevated his own work to a foremost position. “After the discovery by Dr. Faraday of the foregoing principles of galvanic induction, the most important additions to this branch of electricity have been made by Prof. Henry.”

Moyer's biography regrettably deals only sparsely with the last 30 years of Henry's life, after his appointment in 1846 as secretary of the newly founded Smithsonian Institution, a position he did not seek but was honoured to accept when offered. Henry was in effect the sole director, and the job required all his energy and time. Research into the nature of electromagnetism was abandoned, and there is no indication in Moyer's book as to whether or not he followed the developments in this field. It would be intriguing to know his response to the great treatise of James Clerk Maxwell, which was published five years before Henry's death. Did he even know about it? Would he have understood it? Probably not, we suspect.