The Blacksmith’s Motor
Late in 1833 Thomas Davenport, a thirty-one-year-old blacksmith from Brandon, Vermont, visited the Penfield Iron Works in nearby Crown Point, New York. There he saw a three-pound electromagnet lift a 150-pound anvil. Davenport was deeply impressed. At great expense he bought the electromagnet instead of the iron he had come for.
The thought of harnessing the power of an electromagnet to drive machinery came to Davenport “like a flash of lightning,” as he later put it. He envisioned a motive power that would be safer and easier to tame than steam. Steam was an imperfect power, its cost in human lives too great. Electromagnetism would be a benign substitute.
In 1830 Joseph Henry had fashioned a feeble rocking-beam motor in which a bar electromagnet alternately attracted and repelled iron rods, but it was Davenport in July 1834 who created the first rotary electric motor of recognizably modern design. It had a permanent horseshoe magnet pointed downward (the stator) and a U-shaped electromagnet pointed upward that turned (the rotor). A later version, using pairs of electromagnets for both rotor and stator, could revolve at six hundred revolutions per minute.
Davenport’s neighbors in Brandon ridiculed him as the “perpetual motion man” who, through laboring mightily, had produced only “mosquito” power. Hometown skeptics identified another obstacle to electromagnetic power: It was horribly expensive, because the battery’s zinc had to be replenished constantly. On this matter Davenport simply expressed faith that the price of electric power, like that of steam, would fall as the technology was perfected.
Davenport’s main technical challenge was to make motors powerful enough to do useful work. His main practical challenge was to find the money to support his experiments, since he had in effect given up his blacksmithing business. He solicited endorsements from eminent men of science and used them to raise sporadic financial support.
On the mechanical side Davenport’s collaborators included Orange A. Smalley of Brandon; one B. Richardson of Rochester, Vermont; Ransom Cook of Saratoga Springs, New York, who built the patent model; and especially Davenport’s wife, Emily, who not only donated her wedding gown for insulation but kept detailed records of his experiments and suggested the use of mercury in the commutator.
By piecing together financial and technical assistance from various sources, Davenport was able to build ever larger motors. He motorized some small machines, drilled iron and steel, and turned hardwood on a lathe. Davenport’s motor received much favorable press. The New York Herald published an especially enthusiastic article, referring to the motor as a “most extraordinary discovery—probably the greatest of ancient and modern times—the greatest the world has ever seen—the greatest the world will ever see.” It went on to predict that “the days of steam power, and animal power, and water power, are gone forever.” How would this come to pass? The article matter-of-factly reported that electromagnetic power would be one-tenth the cost of steam. No grounds were provided for this belief, and it was to prove wildly wrong.
In 1837 Davenport patented his “electromagnetic engine.” He and Cook found a backer and issued stock, but the enterprise soon collapsed in the Panic of 1837, and Cook sold out. In 1839 Davenport attached one of his motors to a printing press and began publishing The Electro-magnet and Mechanics’ Intelligencer , America’s first journal of electricity. Unfortunately its second issue was its last, for Davenport’s invention, ingenious though it was, had a flaw that doomed its commercial prospects: the high cost of refurbishing the batteries. Davenport returned to blacksmithing in the fall of 1842 and died, broken in spirit and virtually penniless, in 1851.
Davenport was a classic example of an inventor whose creation was premature. With clear vision and firm resolve he had shown that electric motors could drive machinery. Yet the electric motor was quite properly judged impractical. That a technology works as claimed is no guarantee that it will become a successful product. If massive funding had been put into electromagnetic power in the 1840s and 1850s, the appropriate ancillary technology, such as steam-powered dynamos, might have been built. But the judgment of financiers moved the cutting edge of technology elsewhere, to products that seemed to promise more immediate profits.