Page:The character and extent of air pollution in Leeds - (A lecture delivered before the Leeds Philosophical Society, on March 3rd, 1896.) By Julius B. Cohen (IA b21534160).pdf/10

10 are correct, there should be 1&middot;2 milligrammes of soot at any moment in 100 cubic feet of Leeds air, on a working day. I made this calculation before I began my experiments, in order to ascertain approximately the quantity of soot I must prepare myself to deal with. The following is a diagram of the apparatus employed for estimating the solid matter in Leeds air.

The apparatus was in work daily, except Sundays, from the middle of April to the middle of June, 1894, i.e., 50 days, 20 cubic feet of air being aspirated daily. The average of two sets of experiments gave 1&middot;2 and 1&middot;16 milligrammes respectively in 100 cubic feet, which comes very close to the estimated quantity. It is needless to state, that at the end of one day, the exposed end of the plug was perfectly black, from the accumulation of particles of soot. I think, then, that we shall not be far from the mark in accepting the figure I have given, viz.: 20 tons a day, or 6,000 tons, value £300, a year, as the minimum loss of fuel in the form of soot.