By Russ Sherwin

In the latter half of the nineteenth century, one of the best power sources the small farmer had, or could readily obtain, was horses. If he didn’t have his own, he could borrow or rent some for a short period of time. A horse just requires a little water and some hay for fuel and he’s good to go. And it’s generally scalable: Need more power? Get more horses. Then, because of advances in crop processing machinery, a need developed for stationary rotary power. The problem is, how do you turn a walking horse into a rotating shaft?

One early solution was a treadmill on which a horse simply walks. Power could be taken from these to drive other machinery. Treadmills were designed for a wide variety of animals besides horses and mules, including dogs, sheep and goats. Although simple, compact and practical for small jobs requiring small amounts of power,practical limitations constrained the designs to two horses at most.

A new machine appeared in the form of the multi-horse sweep, a merry-go-round device that would, theoretically, accept as many horses as you had room to harness to the wheel. They went by various names, and there were dozens of manufacturers such as J. I. Case, Woodbury, Pitts-Carey and Dinger-Woodbury, each with variations on the theme.

One common term for the sweep or merry-go-round type of machine was, uniquely enough, a ‘horse-power.’ It was also called a ‘sweep-power’, or simply a ‘power’. Up to eight, twelve or sixteen horses could be harnessed in pairs around the wheel. The horses marched endlessly around the circle, pulling the merry-go-round which drove a smaller gear with a shaft extending out beyond the circle from which power could be obtained. The horses had to step over the shaft every time they came around. The ‘driver’ stood in the middle on a raised platform with a whip to keep the horses moving. There were, of course, practical limitations. You can imagine the mess when, inevitably, one of the horses stumbled, bringing the whole thing to an inglorious halt.

Patent Drawing for a Horse Powered Treadmill (Illustration Courtesy of the Author).

A simple analog of the horse-power is a hand-crank eggbeater. If you lay the eggbeater horizontally and attach a miniature horse to the crank, as he walks around he will turn the beaters. Of course he has to jump over the beater shafts each time he comes around. In place of one of the beaters you affix a pulley with a belt to a threshing machine. A very small threshing machine to be sure; but then, you have a very small horse!

An interesting side note relating to the horse-power machines is how the quantitative unit of ‘horsepower’ was developed in the first place. We all understand that our car’s engine is rated in horsepower, but few of us understand just what that means or how it came to be termed that. It has something to do with horses, probably, but what? Well, typically the average draft horse was considered as having the tractive power to pull 1/8 of its weight for 20 miles traveling at 2.5 miles per hour.  Thus, a typical 1,500-pound draft horse could develop 33,000 foot pounds per minute which became defined as one horsepower (hp.).

The horse-power machine was a relatively short lived phenomenon due to the increasing power demands of the rapidly developing farm implement industry. Steam tractors, huge, heavy, wheezing, clanking monstrosities became the power source of choice before they were replaced by petroleum based internal combustion tractors.

If you visit even a medium sized farm nowadays, you will find great green, blue, red, orange or yellow machines rolling across hundreds of acres of perfectly groomed and level farmland, planting, harvesting, bailing, threshing, packaging and delivering all manner of farm goods. They are fully enclosed and air conditioned, they follow paths determined by GPS, they are self-propelled by enormous diesel engines, they are equipped with stereo, AM-FM receivers, radio communications, refrigerators for cold drinks and plush leather seats. They are also very likely commanded by 16-year old girls working their first summer jobs between high school classes.

It was not always so easy.

(Days Past is a collaborative project of the Sharlot Hall Museum and the Prescott Corral of Westerners, International. The public is encouraged to submit articles for Days Past consideration. Please contact Assistant Archivist, Scott Anderson, at SHM Archives 928-445-3122 or via email at archivesrequest@sharlothallmuseum.org for information.)