ALMOST EVERY WAR IN AMERICAN HISTORY HAS inspired valuable innovations in military technology. The Civil War, for example, saw the first major use in the United States of rapid-fire weapons, land and naval mines, observation balloons, and ironclad ships, among other inventions. One of the most farsighted (if impractical) schemes of that conflict was devised in 1862 by an Indianapolis machine-shop owner named Albert E. Redstone. He proposed to build an armorclad, steam-operated “engine of war”—what today would be called a tank.

The idea of a movable armored weapon was not new by any means. Judges 1:19 relates how Judah “could not drive out the inhabitants of the valley, because they had chariots of iron,” and in 1482 Leonardo da Vinci designed a wood-armored chariot to be propelled by four men turning hand cranks.

The advent of steam power led to renewed proposals for armored war vehicles. One was designed in 1854, at the time of the Crimean War, but was never followed up, though a British patent was issued the following year. Then, on August 18, 1862, Redstone sent his plans to U.S. Secretary of War Edwin M. Stanton. With imperfect spelling, he called his invention the “Anihilator.” Inspired by the newly launched ironclad warship Monitor , he described it as a “land monitor.”

The crew would consist of two men, one to drive and one to shoot. The vehicle would be protected by two coats of iron armor with a gap in between. Glass windows would provide a view of the battlefield, and “side knives” resembling sickles could be extended “for cutting down infantry or Cavalry.” A 25-horsepower steam engine of Redstone’s patented design would provide propulsion.

Most innovative of all was the vehicle’s intended armament, a multiple-barrel Catling gun that would let the Anihilator “run into the enemy lines & fire 5,000 shots in 5 to 12 minutes impregnable to the enemy’s assaults.” Richard J. Catling, inventor of the rapid-fire weapon that bears his name, had built his first prototype earlier that year at his shop in Indianapolis, and Redstone no doubt had seen or heard about its public demonstration there.

No reaction to Redstone’s letter survives, but it is doubtful the plan got much consideration. The Army’s chief of ordnance was the crusty James Wolfe Ripley, a War of 1812 veteran who shunned newfangled gimmicks, such as breechloading rifles. In June 1861 he had complained, “A great evil now specially prevalent in regard to arms for the military service is the vast variety of new inventions.”

Could Redstone’s scheme have succeeded? Probably not. Even ignoring the unbearable heat that would have built up inside, Redstone’s projections of his tank’s capabilities were far from realistic. According to R. P. Hunnicutt, the author of Bradley: A History of American Fighting and Support Vehicles (Presidio Press, 1999), Redstone’s estimated weight of 1,800 pounds was “very optimistic.” Moreover, because of its “low ground clearance and a considerable overhang of the hull,” the Anihilator’s “mobility would have been extremely limited.… Even a shallow ditch or hole would immobilize the vehicle completely.”

Not until early in the twentieth century did “caterpillar” tracklaying technology, originally developed for farm tractors operating on marshy ground, begin to be applied to military vehicles. When combined with internal combustion, mass production, and improvements in weaponry, this advance finally allowed tanks to assume an important role in the later stages of World War I.