The Engineering Association of the South.
At the meeting of the Engineering Association of the South, Nashville, Tenn., July 13, the subject of “Smoke Prevention” was presented by Professor Olin H. Landreth of Vanderbilt University. The paper discussed successively the causes, the effects of smoke, and the remedies for it. Objectionable smoke comes mostly from bituminous coal, other fuels producing very little smoke. When fre-h coal is thrown on incandescent coal, there at once begins the distillation of the more volatile hydro-carbons, which distilled matter is burned if sufficient oxygen is present and the temperature is sufficiently high, but which otherwise passes up the chimney as yellowish fumes. As the fresh coal becomes more highly heated, the less volatile hydro carbons are distilled, and arc decomposed at a temperature much below that necessary for the combustion of the carbon liberated, about 2COO degrees Fahrenheit, a temperature so high as to give considerable margin of opportunity for this portion of the carbon to escape unburned. It is this free unburned carbon in a finely divided state that, while incandescent, produces the luminous flame, and, when cooled, the clouds ol smoke that issue from the chimney and afterward settle as soot. After the volatile matter is driven off, the fixed carbon remains, and in burning produces but little flame and no smoke, since the particles of carbon are not detached from the solid mass till combustion takes place. As to the effects of smoke production, the fuel loss in the smoke itself is but small, estimated at one-sixth of one per cent ; but the causes of smoke are also the causes of imperfect combustion and consequent waste of fuel in the form of invisible gases, carbonic oxide and light hydrocarbons, and the presence of smoke indicates this parallel waste. Aside from the fuel waste, the effects of smoke outside the furnace make its abatement of public interest. It is authoritatively stated that the residuum of smoke in the lungs induces consumption of an incurable character ; and that, in the city of Pittsburgh, Pa., the death rate was 1.62 per 1000 lower during the eight years in which the use of natural gas almost freed the city from smoke, as compared with the pieceding eight years ; and that, sinee the partial return of smoke, the rate has increased 2.57 per 1000. Carbon in a finely divided state is an easy vehicle both for noxious gases and organic impurities. The insidious soot pervades and defaces public and private buildings, and calls for fruitless efforts for cleanliness when cleanliness is impossible. Smoke is objectionable from the loss of light and increased cost of artificial light ; also from the repression of sesthetic tendencies and consequent mental and moral discouragement. Consideration of 1 he causes suggests the agencies and the mechanical devices for the prevention of smoke ; these latter, so far as pertains to steam boilers, are classed as mechanical stokers, air flues in the walls and grate-bars, coking arches, dead plates, downdraft furnaces, steam jets for injecting air and mixing the gases, baffle plates and double fnrnaces. Smoke prevention must be accomplished by educating the public to consider smoke a nuisance that unquestionably can and should be abated, lor the smoke producers are very slow to be convinced that this abatement is to their interest. Following the influence of public sentiment, laws are to be enacted, and provision made for their enforcement, and for furnishing to smoke producers, when desired, professional advice regarding the means and appliances for smoke prevention. The paper gives the statutes passed in Chicago, Cincinnati, Cleveland, Pittsburgh, New York, Rochester, Boston, Denver, the State of Ohio, and the city of Birmingham, England, with statements of the success attained in preventing smoke in these localities, success in each case being proportional to the vigor of action taken. The paper contains descriptions of various mechanical devices for smoke consumption and a list of literature on the subject.
The next meeting of the association will be held September 14.