MECHANICS AXD USEFUL ARTS. io 



found to be worse than useless. The generation of the gas and the admis- 

 sion of the air through the uncovered portion of the bars, created such 

 irregularity as to defeat all efforts at uniformity, and it was impossible, by 

 any self- acting valves, to obviate the effects of such irregularity. 



ON A NEW SMOKE-CONSUMING FIRE-PLACE. 



At a recent meeting of the Society of Arts, Dr. Arnott, F. R. S., read 

 a p:iper " On a New Smoke Consuming and Economical Fire-place, with 

 additions for obtaining the healthful warming and ventilation of houses." 

 The author commenced by stating that the great evils connected with the 

 common coal fires were : 1. Production of smoke ; 2. Waste of fuel ; and 

 3. Defect of warming and ventilation. After reviewing the evils arising 

 from smoke in the interior of houses and in the external atmosphere 

 which in the washing of clothes alone cost the inhabitants 1,500,000?. 

 more than the same number of families residing in the country, besides 

 being inimical to health the question of waste fuel was examined, and 

 the opinion of Count Kumford was quoted, who declared that five-sixths 

 of the whole heat produced in an ordinary English fire went up the 

 chimney with the smoke to waste. This estimate was borne out by the 

 facts observed in countries where fuel was scarce and dear, as in some parts 

 of Continental Europe, where it was burned in close stoves, that pre- 

 vented the waste, and with these a fourth part of what would be con- 

 sumed in an open fire sufficed to maintain the desired temperature. The 

 axithor then proceeded to observe that if fresh coal, instead of being placed 

 011 the top of a fire, where it must unavoidably emit visible pitchy vapor 

 or smoke, be introduced beneath the burning red-hot coal, so that its pitch 

 in rising as vapor must pass among the parts of the burning mass, it 

 would be partly resolved into the inflammable coal-gas, and would itself 

 burn and inflame whatever else it touched. Various attempts had been 

 made to feed fires in this way, of which the most important was that intro- 

 duced by Mr. Cutler about thirty years ago. He placed a box filled with 

 coal immediately under the fire, with its open mouth occupying the place 

 of the removed bottom bars of the grate, and in the box was a movable 

 bottom supporting the coal, and by pressing which the coal was lifted 

 gradually into the grate to be consumed. The apparatus for lifting, how- 

 ever, was complicated and liable to get out of order, which, with other 

 reasons, had caused this stove to be little used. In Dr. Arnott's new 

 fire-place, the charge of coal for the whole, day was placed immediately 

 beneath the grate, and was borne upwards as wanted by a piston in the 

 box, raised simply by the poker iised as a lever, and as readily as the wick 

 of an argand lamp was raised, and the fire was under command as to its 

 intensity almost as completely as the flame of a lamp. To light the fire, 

 wood was laid on the upper surface of the fresh coal filling the box, 

 and a thickness of three or four inches of cinders or coked coal left from 

 the fire of the preceding day was placed over it. The wood being then 

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