"The fact that the furnace, engine, boiler, governor, pump, gauge-cocks, safety-valve, steam-gauge, and water-bottom (which is also a heater and mud-drum), composing a 10 horse-power machine, can be set up on a floor space of 4½ feet, and yet be only 9 feet in height, is hardly credible until one comes to examine the admirable arrangement of the different portions.
"The compactness of this machine renders it easily transportable, and its comparatively light weight (ranging from 1280 pounds in the 2 horse-power to 4300 in the 10 horse-power) allows it to be placed directly in the story or room in which its work is required."
Emory Edwards, The Practical Steam Engineer's Guide, 5th ed. (Philiadelphia, 1887)
Engraving from T. J. Fales, The Baxter Portable Steam Engine (New York, 1878)
In the 19th century a leading example among small steam engines was the Baxter portable engine. It was a combination of engine and boiler in a single, movable unit, the invention of William Baxter of Newark, New Jersey. The manufacture of the Baxter engine was undertaken by Samuel Colt.
The production of the Baxter engine began in 1868 at the large works of Colt's Fire Arms Manufacturing Company in Hartford, Connecticut. The inventor's object was a small, compact, safe, and economical steam engine "which should be so easy to manage as to warrant its introduction for uses among the people:"
Interchangeable in all its parts, the engine was consequently perfect in its construction. It was light in weight, ranging from 1,280 lbs. for the 2-horsepower size to 4,300 lbs. For the 10-horsepower model.
"The whole machine takes up no more space than a good sized stove" and may be placed directly in the room or story where required. Consuming less fuel than any other engine of equal power, the 3-horsepower size used only a half bushel of anthracite a day and rarely exceeded one ton in a month.
"If the portion becomes lost or broken, it can be instantly replaced with another exactly similar, as every part is made by special tools, on the same principle as the Waltham watches or Colt's rifles and pistols."
A boy can run it "with very little teaching."
The builders guarantee the Baxter engine to be "more simple, safe, durable and economical than any other small power machine in the world."
In July 1871, 100 Baxter engines were found widely scattered over the country. By the fall of 1872 more than 50 were in New York City alone, and a year later over 800 were in daily use, a figure that increased to thousands in May 1874, as well as many in use abroad.
The portable engine, declared John C. Merriam, in 1868, "has lately come into general use, and, like the stationary, is made of various forms, in all of which it resembles the latter, with the exception of placing the engine directly upon, or against the boiler. These engines are used wherever it is necessary to do work sufficiently great to pay for them, but not for permanent business." Eighty Years' Progress of the United States: A Family Record of American Industry, Energy, and Enterprise (Hartford, Conn., 1868), page 255).
Portable engines, "are generally less complicated, their price is less, and they are complete when they leave the manufacturer and ready to put into immediate operation, requiring no mason-work or other expense to set them up." American Artisan, n.s. 4 (Jan. 9, 1867): 146). Confusion arose from the practice of applying the term portable also to similar arrangements mounted on wheels, frequently made locomotive. See Knight's American Mechanical Dictionary, vol. 2 (New York, 1877), pages 1769-1770, with drawings.