120 FUELS 



If decomposition continues still further and absolutely all 

 gases are expelled, graphite a form of pure carbon results. 

 Graphite is a shiny black mineral much used in commerce, and 

 known to the housewife as an ingredient of stove polish. 



The smoke nuisance. The dense smoke given forth from 

 puffing locomotives, from factory smokestacks, and from home 

 chimneys is objectionable to all lovers of cleanliness. It settles 

 on curtains and draperies and dulls them ; it settles on marble 

 and robs it of its purity ; it settles on freshly papered walls and 

 ages them rapidly; in fact, it places its grimy hand on every- 

 thing and leaves a smudge on whatever it touches. In large 

 manufacturing cities like Pittsburgh, the atmosphere reeks with 

 smoke. The most secluded corners are permeated with smoke- 

 laden air, and house furnishings of somber hue must be used 

 unless the housewife is willing to devote herself unceasingly to 

 the laundry, or is able to replace the delicately colored articles 

 as soon as they are discolored. The smoke nuisance is due to 

 the use of soft or bituminous coal. Until the frightful strike in 

 the anthracite coal mines about fifteen years ago, soft coal was 

 rarely used for fuel. At the time of this strike, hard coal was 

 locked up in the mines and bitter winter knocked at the door. 

 Then soft coal came into use. Since that time it has grown ex- 

 ceedingly popular with manufacturers, and because of its greater 

 cheapness its popularity will doubtless continue. We can readily 

 understand why soft coal is responsible for the smoke nuisance. 

 In soft coal the process of destructive distillation has not gone 

 far. Gases are set free when it is heated in stoves and furnaces, 

 and they burn with a yellow flame, from which smoke issues. 

 The smoke consists of unburned carbon particles which float in 

 the air for a time and finally settle as fine dust does. There is 

 no indication that the use of soft coal will be abandoned, so there 

 is no immediate prospect of freeing our city atmosphere of 

 smoke. 



