Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 1, 1802).djvu/336

!<H] BOI ventioa. This, he conceives, prin- cipally consists in the three follow- ing circumstances : 1. In the peculiar mode of con- structing the furnace, or setting the boiler, and of placing the lire, not immediately under, but a littie in front, or at one side of it, whereby the flame and hot air can get access to every part of the ves- sel, and not only strike with force against its bottom, but also with equal effect reverberate against, and violently embrace its sides, and ■whole external surface; unlike every former contrivance, the most perfect of which could only cause the flame and hot air to act partially upon the bottom and sides of the vessel. 2. In the elevated situation, and smallness, of the aperture leading from the furnace towards the chimney; whereby the flame and hot air are impeded in their pro- gress to the atmosphere, and com- pelled to tarry in the cavity of the furnace, and occupy every part thereof much longer than they otherwise would do. This effect. in stopping, checking, and as it were arresting the flame and hot air, in their attempt to escape into the atmosphere, Mr. Hindmarsh considered as not only new, but singularly beneficial 3 for, by this means, the flame and hot air are detained in the very place where their presence is most wanted, and constrained to give forth their en- ergies with an impetus against the bottom and sides of the vessel to be heated : whereas, in none of the furnaces heretofore erected, was any effectual stop interposed between the fire and the chimney, to cause the flame and hot air to dwell under and round the sides of the vessel; but they pasacd ta- BOI pidly off into the atmosphere, either by a direct communication through the chimney, or indirectly, but al- most as speedily, by flues ; or else by a drain (as it is called), the aperture of which is equal in di- mensions to that of the chimney itself. 3. In an open space between the furnace and chimney, called by the Patentee a box, trap, or reser- voir, and intended as a receptacle of the flame, hot air, and smoke, after they have quitted the fur- nace, and passed through the small aperture as above described. This space, or reservoir, for the flame, hot air, and smoke, being closed at the top and external sides, and open only at the bottom outwards, for the purpose of permitting the smoke, &c. to pass off into the chimney, still farther checks and detains the flame and hot air in the furnace ; and being itself constantly full of warm air, smoke, &c. causes the heat to be reverberated against the sides and bottom of the vessel or boiler, and effectually prevents the admission of the cold atmos- pheric air from the chimney, which, on the old plans of construction, is found by experience to rob the fur- nace and vessel of more than half the supply of heat which any given quantity of fuel is capable of yield- ing. The valves, sliders, and dam- pers, are not essential parts of the invention, but merely as regulators, which, in many cases, may be altogether omitted, without detri- ment to the operation of the lire. Aldiough Count Rumford has successfully extended his researches to discover the most economical plan in the management of fire, and the generation of heat for culi- nary and other purposes, it does not appear from his writings, that he had