8 



NEW SMOKE-CONSUMING AND FUEL-SAVING FIRE-PLACE. 



[1854. 



ligliting the fire, to allow of tlie removal of any coal-dust or 

 ash which has fallen down past the edge of the piston. 



Before lighting the fire iu the morning, the little ash which 

 remains with this form of combustion is removed from off the 

 piston. 



The fire is extinguished at night by allowing it to exhaust 

 itself, or by lifting out the few lumps of coke or caked coal 

 which remain. The morning charge should be such that 

 enough cinder or coke may be left for the smokeless lighting of 

 the next day. 



By the means now described, then, the first-named evil of 

 ihe production of stnoke is effectually combatted. 



II. WASTE OF FUEL. 



We now come to consider whether the v;aste of fuel which 

 occurs in common open fires can be prevented. 



Count Rumford, as the result of his own experiments already 

 referred to, declared that 5-6ths bf all the heat produced. in a 

 common open fii'e passed up the chimney with the smoke, . and 

 therefore to waste ; and he apjsealed in corroboration to the 

 experience of the Continent of Europe, where close stoves are 

 used, which do not thus waste heat up the chimney, and 

 where a much smaller allowance of fuel than is here needed in 

 open fires sufiiees. I have, in my own house, a striking illus- 

 tration of the matter in a peculiar enclosed fire, which, for four- 

 teen years past, in a large dining-room, has maintained, day 

 and night, from October to May, a temperature of 60 degrees 

 or more, accompanied with good ventilation, by an expendi- 

 ture of only 121bs. of coal for 24 hours, or about a fourth of 

 what would be used in an open fire burning for 15 or 16 hours. 

 This fire is lighted about the beginning- of October, and is not 

 extinguished at all until the following May. The aperture by 

 which the fresh air enters the stove to maintain the combustion 

 suflicient to warm that room, is about three-quarters of an inch 

 in diameter. If this be compared with the aperture of a com- 

 mon chimney-pot, which has a diameter of ten inches, and an 

 area or size 160 times greater than my stove, and one thinks of 

 the rapidity with which a column of dense smoke filling that 

 pot escapes from it when the fire is burning briskly ; and re- 

 flects further that such column consists entirely of the warmest 

 air from the room, blackened by & little pitchy vapour from the 

 fire, there is proof of prodigious waste, and room for reasonable 

 hope that a saving is possible. To see how a saving may be 

 effected, the exact nature of the waste in such cases has now to 

 be explained : — A single mouthful of tobacco smoke, on issuing 

 immediately diffuses itself so as to form a cloud larger than the 

 smoker's head, and soon would contaminate the whole air of a 

 room, as would also the smoke and smell of wood, paper, or 

 or combustible burned in a room. Now, the true smoke of a 

 common fire is not the whole of what is seen issuing from the 

 chimney top, but only little driblets or jets which shoot up or 

 isssue from the cracks in the upper surface of coal which forms 

 the fire. These jets, however, quickly diffuse themselves, like 

 the tobacco smoke, in the air around them, that is to say, in 

 the large volume which fills the space left over a common fire, 

 and over the hobs, if there be such, at the side of the grate. 

 The whole of the air so contaminated, and which may be in 

 volume -30, 50, or 100 times greater than that of the tree 

 smoke, is then all called smoke, and must all be allowed to 

 ascend away from, the room. It is evident, then, that if a 

 cover or hood be placed over a fire, such as is represented by 



the letters y a 6 in the diagi-am, so as to prevent the diffusion 

 of the true smoke or the entrance of pure air from around to 

 mix with it, except just what is necessary to burn the inflam- 

 mable gases which rise with the true smoke, there would be a 

 great economy. This has been done iu the new fire-place, 

 with a saving of from one-third to one-half of the fuel required 

 to maintain a desired temperature. .In a room the three 

 dimensions of which are 15 feet, 13 a feet, and 12 feet, with 

 two large windows, the coal burned to maintain a temperature 

 of 55 degrees in the coldest winter days, has been 18 lbs. for 

 19 hours, or less than a pound per hour. 



And it is to be remarked that not nearly the whole possible 

 saving has been effected in the case refen-ed to ; for the grate 

 was an old one imperfectly altered, and as the true smoke, 

 little diluted, is very hot air when it leaves the ignited coal, 

 and if it were made to pass,, in contact with a vessel contain- 

 ing water or colder air, it would give up for use a considerable 

 part of its heat. In many cases such saving will be profitably 

 effected. Under the present imperfect forms of open fire, the 

 whole of the hot smoke passes away as certainly as here, but 

 at present is so much diluted with the colder air of the room, 

 that ordinary observers do not perceive, and, consequently, 

 do not regret the fact. 



In many cases the contraction of the space over the fire will 

 be more conveniently made in brick-work than by a metallic 

 hood. Where the'hood is used, unless it be made a boiler or 

 watei'-vessel, it should be lined with tile to prevent that over- 

 heating which would cause in the room some smell of heated 

 metal. 



The stalk of the hood at y passes closely through a plate 

 or other stopping at the bottom of the chimney, so that no air 

 shall enter the chimney but through the hood; and there is a 

 throttle-valve or damper in the hood-stalk, at t, giving perfect 

 control over the current of air that passes through. No part 

 of the apparatus is more important than this valve or damper, 

 and its handle or index must be very conspicuous, and have 

 degrees of opening marked on its plate as clearly as the points 

 are marked on a compass-card. When the valve is cjuite open, 

 the chimney acts to quicken the combustion, like that of a 

 blast-furnace, or like a forge-bellows, but, by partially closing 

 the valve, the current may be diminished, until only the most 

 tranquil action remains. The valve should not be open in 

 general more than just enough to let all the burned air or thin 

 smoke, which is scarcely visible, pass through. When the 

 valve is once adjusted to the usual strength of chimney action, 

 it requires little change afterwards. 



In many cases it is desirable to be able 40 command and 

 modify, by a movable plate, the size of the front opening of 

 the hood or fire-place, as well as the opening of the chimney 

 throat. By the proper adjustment of the two, the desirable 

 brightness of the front of the fire may be maintained. 



The chimney-flue above the upper opening of the hood should 

 have its sides made slanting, so as not to harbour dust or 

 any soot which, from any careless use of the fire, might be 

 produced. The size of the chimney-flue is not important. 



The answer then to the second question, as to the possibility 

 of saving fuel, is by the facts here adduced, given in the 

 afiirmative. 



(To be continued.) 



