Inventions in the Century

by William Henry Doolittle

The heat obtained from stoves is effected by radiation—the throwing outward of the waves of heat from its source, while the heat obtained from a hot-air furnace is effected by convection—the moving of a body of air to be heated to the source of heat, and then when heated bodily conveyed to the room to be warmed. Hence in stoves and fireplaces only such obstruction is placed between the fire and the room as will serve to convey away the obnoxious smoke and gases, and the greatest facility is offered for radiation, while in hot-air furnaces, although provision is also made to carry away the smoke and impure gases, yet the radiation is confined as closely as possible to chambers around the fire space, which chambers are protected by impervious linings from the outer air, and into which fresh outdoor air is introduced, then heated and conveyed to different apartments by suitable pipes or flues, and admitted or excluded, as desired, by registers operated by hand levers.

There are stationary furnaces and portable furnaces; the former class enclose the heating apparatus in walls of brick or other masonry, while in the latter the outer casing and the inner parts are metal structures, separable and removable. In both classes an outer current of pure air is made to course around the fire chamber and around among other flues and chambers through which the products of combustion are carried, so that all heat possible is utilised. Vessels of water are supplied at the most convenient place in one of the hot-air chambers to moisten and temper the air, and dampers are placed in the pipes to regulate and guide the supply of heat to the rooms above.

After Watt had invented his improvements on the steam engine the idea occurred to him of using steam for heating purposes. Accordingly, in 1784, he made a hollow sheet-iron box of plates, and supplied it with steam from the boiler of the establishment. It had an air-escape cock, and condensed-water-escape pipe; and in 1799 Boulton and Watt constructed a heating apparatus in Lee’s factory, Manchester, in which the steam was conducted through cast-iron pipes, which also served as supports to the floor. Patents were also taken out by others in England for steam-heating apparatuses during the latter part of the 18th century.

Heating by the circulation of hot water through pipes was also originated or revived during the 18th century, and a short time before Watt’s circulation of steam. It is said that Bonnemain of England, in 1777, desiring to improve the ancient methods of hatching poultry by artificial heat—practised by both ancient and modern Egyptians ages before it became a latter day wonder, and taught the Egyptians by the ostriches—conceived the idea of constructing quite a large incubator building with shelves for the eggs, coops for holding the chickens, and a tube for circulating hot water leading from a boiler below and above each shelf, and through the coops, and back to the boiler. This incubator contains the germs of modern water heaters. In both the steam and water heating systems the band or collection of pipes in each room may be covered with ornamental radiating plates, or otherwise treated or arranged to render them sightly and effective. In one form of the hot-water system, however, the collection of a mass of pipes in the rooms is dispensed with, and the pipes are massed in an air chamber over or adjacent to the furnace, where they are employed to heat a current of air introduced from the outside, and which heated pure air is conveyed through the house by flues and registers as in the hot-air furnace system.

The hanging of the crane, the turning of the spit, the roasting in ashes and on hot stones, the heating of and the baking in the big “Dutch” ovens, and some other forms of cooking by our forefathers had their pleasures and advantages, and still are appreciated under certain circumstances, and for certain purposes, but are chiefly honoured in memory alone and reverenced by disuse; while the modern cooking stove with its roasting and hot water chambers, its numerous seats over the fire for pots, pans, and kettles, its easy means of controlling and directing the heat, its rotating grate, and, when desired, its rotating fire chamber, for turning the hot fire on top to the bottom, and the cold choked fire to the top, its cleanliness and thorough heat, its economy in the use of fuel, is adopted everywhere, and all the glowing names with which its makers and users christen it fail to exaggerate its qualities when rightly made and used.

It would appear that the field of labour and the number of labourers, chiefly those who toiled with brick and mortar, were greatly reduced when those huge fireplaces were so widely discarded. This must have seemed so especially in those regions where the houses were built up to meet the yearning wants of an outside chimney, but armies of men are engaged in civilised countries in making stoves and furnaces, where three-quarters of a century ago very few were so employed. As in every industrial art old things pass away, but the new things come in greater numbers, demand a greater number of workers, develop new wants, new fields of labour, and the new and increasing supply of consumers refuse to be satisfied with old contrivances.

In the United States alone there are between four and five hundred stove and furnace foundries, in which about ten thousand people are employed, and more than three million stoves and furnaces produced annually, which require nearly a million tons of iron to make, and the value of which is estimated as at least $100,000,000.

The matter of ventilation is such a material part of heating that it cannot escape attention. There can be no successful heating without a circulation of air currents, and fortunately for man in his house no good fire can be had without an outflow of heat and an inflow of cooler air. The more this circulation is prevented the worse the fire and the ventilation.

It seems to many such a simple thing, this change of air—only to keep open the window a little—to have a fireplace, and convenient door. And yet some of the brightest intellects of the century have been engaged in devising means to accomplish the result, and all are not yet agreed as to which is the best way.

How to remove the heated, vitiated air and to supply fresh air while maintaining the same uniform temperature is a problem of long standing. The history of the attempts to heat and ventilate the Houses of Parliament since Wren undertook it in 1660 has justly been said to be history of the Art of Ventilation since that time, as the most eminent scientific authorities in the world have been engaged or consulted in it, and the most exhaustive reports on the subject have been rendered by such men as Gay-Lussac, Sir Humphry Davy, Faraday and Dr. Arnott of England and Gen. Morin of France. The same may be said in regard to the Houses of Congress in the United States Capitol for the past thirty-five years. Prof. Henry, Dr. Billings, the architect, Clark, of that country, and many other bright inventors and men of ability have given the subject devoted attention. Among the means for creating ventilation are underground tunnels leading to the outer air, with fans in them to force the fresh air in or draw the poor air out, holes in the ceiling, fire places, openings over the doors, openings under the eaves, openings in the window frames, shafts from the floor or basement with fires or gas jets to create an upward draught, floors with screened openings to the outer air, steam engines to work a suction pipe in one place and a blow pipe in another, air boxes communicating with the outer air, screens, hoods, and deflectors at these various openings,—all these, separately or in combination, have been used for the purpose of drawing the vitiated air out and letting the pure air in without creating draughts to chill the sensitive, or overheating to excite the nervous.