709 



WARMING AND VENTILATION. 



WARMING AND VENTILATION. 



710 



smoke, he kept the water always nearly at the boiling temperature 

 This apparatus being however both expensive and difficult to manage 

 he dispensed with the water, and surrounded the fire merely with a 

 body of air. In the new form of stove, the fuel is put into a smal' 

 fire-box, enclosed within a larger case of sheet-iron ; the only openings 

 in the outer case being a door at which the fuel is introduced, an air- 

 hole beneath the grate, and a chimney for the exit of smoke, which 

 chimney, being merely a metallic tube three or four inches in diameter 

 can be easily arranged in position. The interior of the outer case is 

 nearly divided into two parts by a partition so adjusted as to cause a 

 continued circulation of the heated air within, and hence an equable 

 heating of the outer ease. The air-vent leading to the fire is provided 

 with a valve, by which the admission of air is rendered more or less 

 abundant according as the fire within is less or more intense. It was 

 one point in Dr. Arnott's system to make the stove a " self-regulating " 

 one, by providing apparatus whereby the valve would open and shut 

 at the proper times to maintain any required temperature ; and he 

 suggests six or eight different modes of arrangement, from which the 

 maker of the stove may select one. Dr. Arnott states : " During 

 the winter, 1836-7, which was very long and severe, my library 

 was warmed by the thermometer-stove alone. The fire was never 

 extinguished, except for experiment, or to allow the removal of 

 pieces of stone which had been in the coal ; and this might have been 

 prevented by making the grate with a moveable or shifting bar. The 

 temperature was uniformly from 60 to 63. I might have made it as 

 much lower or higher as I liked. The quantity of coal used (Welsh 

 stone-coal) was, for several of the colder months, six pounds a day ; 

 less than a pennyworth, or at the rate of half a ton in the six winter 

 months." This kind of stove possesses many advantages ; but it is not 

 free from defects. It is liable to the objection already stated with 

 regard to the unpleasant feeling consequent on the use of all stoves 

 of the kind, and indeed with it more than others ; for owing to the 

 very slight expenditure of fuel, there is little or no change in the 

 atmosphere. 



Numerous varieties of the close stove, bearing more or leas on the 

 above construction, have been brought forward since the publication of 

 Dr. Arnott's first book on this subject in 1838. Each professes to 

 possess some peculiar merit ; but all present these features in common : 

 that the air-hole, by which the combustion is fed, is very small, and 

 capable of adjustment; that there is a body of air to be warmed, 

 external to the grate or fire-box itself, but confined within an outer 

 case; that the consumption of fuel is much smaller than in any 

 variety of open fire-places; and that the flue for carrying off the smoke 

 and gases is small in diameter, and capable of being carried in any 

 direction. In one variety, called the Vesta stove, there is a very 

 ingenious arrangement whereby the ashes can be raked from the grate 

 into an ash-receiver, and new fuel thrown into the grate, without any 

 dust rising into the room, or any air entering the stove except through 

 the customary air-vent. In the different forms of kitchen-ranges the 

 open fire-place is combined with what may be deemed a close stove ; 

 for the oven and hot-closet are representatives of the heated space 

 within the outer case of a close stove. The stoves often employed in 

 shops, halls, &c., are adjusted not so much for the economising of fuel 

 as for the consumption of their own smoke. 



Has-Stoves. In addition to the use of gas for lighting, described in 

 its proper place, gas is now extensively employed for heating, by means 

 of stoves of various kinds. The stoves are mostly cylindrical in form, 

 with openings at the top and bottom. At the lower end, a few inches 

 above the floor, is a ring-burner pierced with numerous minute jet- 

 holes. The top has frequently a sliding valve or damper to regulate 

 the heat. The details vary greatly in ditlerent kinds. Edwards's gas- 

 stove has bulbous-shaped burners of fire-resisting clay, pierced with 

 numerous small holes. Air enters through a lower row of holes and 

 mixes with the gas. The bulb becomes gradually covered with a thin 

 yellow flame. Several such bulbs are combined in various ways, and 

 arranged to form cooking and heating stoves. One form of this stove, 

 the so-called A tmopyre, consists mainly of small cylinders of pipe-clay. 

 Each cylinder is from two to four inches long, and perforated with 

 holes J,th of an inch in diameter. One end of the cylinder is fixed 

 upon a gas-burner ; the gas, being turned on, mixes with the atmo- 

 spheric air in the cylinder ; the little jets which penetrate the minute 

 holes are ignited, the cylinder becomes red-hot, and presents the 

 appearance of a solid red flame. By placing many such cylinder* 

 within another of larger size a very intense heat may be produced, 

 applicable to manufacturing purposes. 



Whatever form a gas-stove may present, its assumed advantages are : 

 a comparative freedom from dust and dirt; a saving of time and labour; 

 facility for adjusting the temperature of a room ; and economy in cost 

 and maintenance. The disadvantages are alleged to be : a diffusion of 

 aqueous vapour, nitrogen, and carbonic acid gas; these ought to be 

 carried off by a chimney or flue, which however is seldom provided for 

 gas-stoves. Moreover, all the bad gases are given oft' near the floor (in 

 gas-stoves, though not in gas-lights), so as to mix with the whole of 

 the air in the room ; and any defect in the burning of any one of the 

 numerous small jets leads to the production of an offensive odour. To 

 leisen these evils, it has been recommended that the stove should have 

 two or three concentric cylinders; that the heated air should be 

 allowed to circulate between them ; that there should be no opening at 



the top ; that a flue of two inches diameter should be placed at about 

 mid-height, to carry off vapour, dust, and deleterious gases ; that there 

 should be an increased amount of metallic and reflecting surfaces to 

 receive the heat ; that only the radiative, not the ascemim, heat should 

 be allowed to combine with the air of the room ; that the size of the 

 stove ought to bear some well-ascertained proportion to the size of the 

 room ; that care should be taken not to overheat the stove, for fear of 

 producing an empyreumatic odour ; and that the gas-jets should never 

 exceed three-quarters of an inch in height. If the flue be long enough 

 to allow the stove to stand near the middle of the room, nearly all the 

 heat will be rendered practically available. In a well-arranged gas- 

 stove seven-eighths of all the heat may be economised. A more equable 

 heat can be maintained by such a stove than by any mode of using coal 

 or coke, on account of the jet-holes remaining constantly of the same 

 size. So far as regards safety, the flue of a gas-stove is not so likely to 

 be highly heated as that of other stoves. Whether such a flue could 

 be made conformable to the decorations or furniture of a room, instead 

 of being an eyesore, is a question worthy the attention of architects 

 and upholsterers. In relation to economical use, it has been calculated 

 that a gas-stove will boil one gallon of water by the expenditure of gas 

 to the value of one farthing; while a pennyworth of gas will bake three 

 quartern loaves or six pounds of meat. On this subject, the application 

 of gas to cooking, see COOKING APPARATUS. 



Warming by Heated Air. In all the arrangements yet described, the 

 stove or fire-place is in the room which is to be warmed, and its heating 

 effects are calculated with respect to that room alone. A notable 

 advance, carried to a great extent in the present day, is to have the fire 

 in an outer or lower apartment, and to carry the heated air from thence 

 in a pipe to the apartment to be heated. The Chinese have been 

 beforehand with us in this matter. In the better class of Chinese 

 houses there are hollow flues extending beneath the floors, and con- 

 nected with a fire-place constructed either against the exterior wall of 

 the apartment to be heated, or else in an inferior room adjoining. The 

 flues are perforated with numerous holes, through which they give out 

 the heated air and smoke to the whole of the under side of the flooring. 

 This flooring consists of flat tiles or flag-stones nicely imbedded in 

 cement, so as to prevent the escape of the smoke or heated air from 

 the flues beneath into the room. After circulating beneath the tiled 

 floor, the smoke escapes by a chimney into the open air. In this 

 arrangement it is obvious that the apartment is warmed by the con- 

 duction of caloric from the warm tiled floor to the air of the room ; 

 and as this conduction proceeds slowly, the tiles retain heat enough to 

 warm the room many hours after the tire has been extinguished. 



Before the improved methods of warming factories came into use, 

 Mr. Strutt, of Derby, devised a form of stove which, under various 

 modifications, was called the " cockle stove," the " Derby stove," and 

 the " Helper stove," for warming his cotton- factories. In these stoves 

 the fire was contained in an iron receptacle, shaped sometimes cylin- 

 drically, sometimes rectangularly ; and at a certain distance from it, 

 encompassing it on every side, was a brick casing or envelope, so that 

 a body of air existed between it and the fire-box. The fire-box hail 

 three openings to the exterior, one to introduce the fuel, one for an 

 ash-pit and air-vent, and one for a chimney ; the exterior envelope 

 had two openings, wholly distinct from the others, one to carry off 

 heated air to the various rooms of the factory, and another to admit a 

 renewed supply of fresh air. Dr. Fyfe describes an arrangement 

 adopted in a church, which may perhaps be taken as a fair example of 

 a numerous class of instances. The body of the church is warmed by 

 two stoves about four feet high, made of cast-metal, and shaped nearly 

 like a bell. A square ash-pit, about a foot high, rests on four balls, 

 and supports a fire-box or furnace. Concentric with this fire-place is 

 an outer case ; the space between the two containing the air which i ; 

 to be warmed. The usual adjustments are provided for the introduc- 

 tion of fuel and of air to feed it, for the exit of smoke, for the entrance 

 of fresh air to the air-chamber, and for the exit of the heated air to 

 perform its wonted office. The air-tubes, communicating with the 

 air-chamber of the stove, are conveyed along the lower edge of the 

 gallery of the church ; and small branch pipes opening from them at 

 regular intervals give out a stream of hot air which mingles with the 

 cold air of the building. The fires are lighted early on the Sunday 

 morning. From this time till the congregation assembles the fires are 

 constantly supplied with fuel, and a supply of heat is thus kept up 

 sufficient to warm the whole interior of the church during the time of 

 divine service. A stove such as this is likely to give a tainted and 

 offensive character to the air, like the common German stoves, unless a 

 rapid current be kept up. Uence a change has been occasionally intro- 

 duced, by having the outer casing made of brickwork, instead of metal, 

 and by making its dimensions much larger, an arrangement which heats 

 the outer case less intensely, and provides a larger body of air heated 

 to a lower temperature. 



Very numerous varieties of the hot-air apparatus have been brought 

 into use ; but the principle on which they all act can readily be under- 

 stood. When the nave and dome of St. Paul's cathedral were recently 

 itted up for Sunday evening services during the winter, six stoves, 

 constructed on a plan devised by Mr. Goldsworthy Gurney, were placed 

 in the crypt. Gratings admitted the heated ah- from these stoves into 

 the body of the cathedral. The vitiated air escaped by openings at 

 the top of the dome. Each stove was a cylinder, with radiating wings 



