900 



Popular Science Monthly 



is the only city where people habitually 

 have their wall paper cleaned once or 

 twice a year by a professional cleaner. The 

 city was spending more than $730,000 for 

 artificial light in the daytime. 



Stringent smoke-abatement ordinances 

 were adopted in 1914, and in the following 

 year it was reported that the amount of 

 smoke emitted had been reduced 75 per 

 cent. Pittsburgh has a Smoke Bureau, 



smoke. Thus many American cities pro- 

 hibit "dense smoke," or "black, thick and 

 continuous smoke," or smoke intercepting a 

 certain percentage of light. But it appears 

 that while the adoption of anthracite coal or 

 coke as fuel will render the discharge of 

 smoke less visible, it will not materially 

 reduce the emission of dust or fine cinder. 

 Another important point brought out by 

 the Chicago investigations is the extent to 



Pittsburgh's sootfall map. To determine the amount of solid matter or soot in the atmosphere, 

 its distribution and composition, stations were selected in various parts of the city. The weight 

 of the sootfall in grams at each station for each month was calculated. Pittsburgh's annual soot- 

 fall was found to be 1,031 tons per square mile. That of Leeds, England, is from 26 to 539 tons 



which costs the city $i i ,000 per annum, and 

 which now effects an annual saving to the 

 community of several million dollars. The 

 methods adopted to diminish the smoke 

 include changes to gas, coke and low- 

 volatile coals, installation of down-draft 

 boilers, inclined chain-grate stokers, under- 

 feed stokers, steam jets and extension stacks. 

 Another city in which elaborate investi- 

 gations have been made is Chicago. Dr. 

 W. F. M. Goss, of the University of Illinois, 

 who directed these studies, brought out 

 several interesting facts, one of which is 

 that too much importance has generally 

 been attached to the mere visibility of 



which the atmosphere of a great city is 

 polluted by forms of dust not due to smoke. 

 Exact measurements of the amount of 

 solid matter contributed to the atmosphere 

 by smoke have been made more extensively 

 in Europe than in America. Measure- 

 ments of sootfall made at twelve stations in 

 Pittsburgh in 1912-13 indicated an annual 

 average deposit of soot in that city amount- 

 ing to 1,031 tons per square mile. In Leeds, 

 England, the sootfall ranges from 26 to 539 

 tons per square mile in different sections of 

 the town. London's average is 248 tons 

 for the whole city and 426 tons in the 

 central districts. In the center of Glasgow 



