TRANSACTIONS OF SECTION G. 489 



2. Smoke Abatement: the Possibility of fixing a new Standard of Smoke 

 Emission from Factory Chimneys. By Dr. J. S. Owens. 



From the point of view of smoke emission the present position of the manu- 

 facturer who burns bituminous coal in his furnace is, that while he knows dense 

 smoke to be unnecessary and wasteful, entire absence of smoke is practically im- 

 possible to attain under working conditions. The question therefore is, What is 

 the least amount of smoke such a manufacturer might be asked to limit himself to if 

 The present legal standard of ' black smoke in sufficient quantity to be a 

 nuisance ' is admittedly unsatisfactory, as black smoke is a thing rarely if ever 

 seen ; also, the blackness alone is no measure of the amount of pollution nor 

 even of the amount of soot per ton of coal burnt. The present standard is there- 

 fore out of date. Meanwhile the public have to breathe polluted air, to suffer 

 in health and pocket, have their buildings injured and disfigured, and their 

 sunshine cut off. 



A sound standard of maximum allowable amount of smoke should be fixed 

 and enforced. Two questions must be answered before such a standard can be 

 fixed : (1) What is the best and most practicable method of measuring smoke? 

 (2) Having decided on (1), what is a fair maximum of smoke emission to fix, as 

 measured by (1) ? 



To answer the first question we must decide exactly wliat we are to measure. 

 We may set ourselves to find out : (1) The total quantity of soot emitted in a 

 given time; (2) the weight of soot emitted as a percentage of fuel burnt; (3) the 

 density or weight of soot per unit volume of flue gas; (4) the ratio only of 

 density to a standard; (5) the colour; (6) the opacity or blackness. 



In deciding the method of measuring we must keep in view : (a) Fair com- 

 parison between chimney and chimney or with standard; (6) ease of application 

 and simplicity; (c) reasonable accuracy; (d) the smoke must be measured from 

 outside factory; (c) the method must be capable of use by a single observer. 



The standard suggested is one of maximum density for maximum time of 

 emission. By density is meant amount of soot per unit volume of flue gas. A 

 smoke of great density would be permitted for a short time only, whereas one 

 of less density might be permitted for a longer time. 



The method of measuring the density suggested is by matching the opacity 

 of the smoke to that of calibrated smoked glasses, each glass representing a 

 certain density of smoke in a column of unit thickness. The final figure for 

 comparison being obtained by dividing the density represented by the glass by 

 the diameter of the chimney. By careful construction and the elimination of 

 certain errors an instrument can thus be made to give a fair basis of comparison 

 with a standard density. The author has devised and experimented with an 

 instrument of this type, with promising results. Certain objections will always 

 remain to such a method of measuring, but the author believes that it is only 

 along such lines that the necessary conditions can be fulfilled. 



The Alkalies Act of 1906 fixes a standard maximum of one-fifth of a grain 

 of muriatic acid per cubic foot in smoke or noxious fumes, and it appears that the 

 time has arrived when the soot from furnaces should be dealt with on similar 

 lines, modified to suit the case. 



3. Continuous versus Intermittent Service in Passenger Transporlaticn. 



By W. Y. Lewis. 



