360 THE A1K OF TOWNS. 



case. Volumes of smoke issue from the top of the chimney until a 

 Bunsen flame is introduced within the lower end of the chimney, when 

 the smoke suddenly ceases. 



Various forms of grates and furnaces have been proposed for pre- 

 venting smoke; some utilize more of the heat, and so reduce the con- 

 sumption of coal; others, by various devices of air inlets at certain 

 times of firing and at special points of the grate, burn up the smoke 

 before it passes to the flue. 



I do not intend, for I do not feel competent, to explain the advantages 

 or disadvantages of the large variety of smoke-pre venting appliances 

 now before the public. A great deal has been writteu on the subject 

 by competent persons, and anyone who wishes for information may 

 very easily procure it. 1 



What are the effects of smoke? Before attacking this question, we 

 ought to consider the extent of the evil. 



I am making determinations, which are now in progress, and though 

 still very incomplete I am able to give an approximate estimate of the 

 amount of solid matter in the air of Leeds which is mainly due to 

 smoke. There is daily sent into the air of Leeds 20 tons of soot, of which 

 one-half ton falls, and of that one-half ton, 20 to 25 pounds stick; that 

 is, are not removable by rain. How have these figures been arrived 

 at? I have found that in the town 100 cubic feet of air contain on 

 the average over 1 milligram of solid matter which is mainly due to 

 smoke. If, now, we take the most thickly populated area of the city as 

 covering 4 square miles, and supposing the sooty atmosphere to pene- 

 trate to a height of 300 feet, the amount of solid matter will be about 

 800 pounds, constantly floating over these 4 square miles. If, further, 

 we assume that the air of the town is renewed from ten to fifty times in 

 twelve hours, according to the strength of the wind (and it is nearer 

 the latter than the former number, as I will show in a moment), this 

 will mean, taking the higher number, rather under 20 tons of smoke 

 delivered to the atmosphere during the working day. Why do I take 

 fifty as the frequency of atmospheric renewal? The difference in the 

 amount of carbonic acid between country air and town air such as is 

 found on the average in industrial centers like Glasgow and Manches- 

 ter, and we may also include Leeds, is 0.01 per cent. There are at least 

 4,000 tons of coal burnt in Leeds every twenty-four hours, yielding 

 12,000 tons of carbonic acid, and in addition there are 300 tons given 

 off from the lungs of the inhabitants, i. e., in all, 12,300 tons. If we 

 keep to the same area of 4 square miles and the same height of 300 



] I should recommend the following pamphlets : The report of "The National Asso- 

 ciation for Testing Smoke-Preventing Appliances/' the address of whose secretary 

 is Mr. Fred Scott, 44 John Dalton street, Manchester. " On the abolition of smoke 

 from steam boilers," by T. Patterson, M. D. Publishers, Chronicle Office, Oldham. 

 "The Smoke Nuisance," by Herbert Fletcher, published by John Heywood, Deans- 

 gate, Manchester. "Report of the Sheffield Smoke Abatement Association," pub- 

 lished by Leader & Sons, 21 Fargate, Sheffield. 





