PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 495 



estate, in the Lehigh region, wliat he called stone coal, upon 

 which for twenty years he experimented at various times. He 

 could occasionally make it burn, but it would hardly be got to 

 burning, by the aid of more inflammable fuel, before it would go 

 out. He was laughed at by his neighbors all this time; but he 

 had the true German perseverance. One day a Yankee clock 

 pedlar, seeing it, discovered the secret of the failure to burn. 

 With a good fire of hickory wood, it would burn and make the 

 kitchen too hot too live in ; but as soon as the wood was burned 

 up, the coal would fall down and go out. So the Yankee went 

 into a blacksmith's shop and constructed a grate, and in that the 

 stove coal would burn. Just as it was in the tide of successful 

 experiment, a messenger arrived at the gate to inform the Gov- 

 ernor that a criminal was about to be executed, and making 

 application for a pardon. "Let him hang," said the Governor to 

 the messenger, " you come into the kitchen and see my stone coal 

 burn." An attempt was next made to burn it in the furnaces of 

 steam engines, but at first without success. At last an engineer 

 having got up a pretty good fire went home, and upon returning 

 to his furnace found it all in a glow, with a good Lehigh fire ; 

 and thus he discovered that the way to burn it is to get it a 

 burning and then let it alone. If the draft is too great, clin- 

 ker will be formad, and the way to prevent it is to diminish the 

 draft. From that time the burning of anthracite in the United 

 States became a fixed fact, and it is now used all over the world. 

 It has in many places banished all other coal, and is the purest 

 and riche^'t source of carbon that the world knows of. 



After it was ascertained that anthracite would burn, the iron 

 manufacturers tried it, and found, after many and long trials, 

 that, with the hot blast and pure anthracite, iron could be made 

 cheaper than in any other way. The anthracite pig has become 

 so cheap in the market that, in the United States, charcoal pig 

 is manufactured only for specific purposes. Thus, at Salisbury, 

 Conn,, iron is made from a pure hemitite, with charcoal, for pur- 

 poses requiring a tough iron, such as the axles of cars, tires, 

 muskets, swords, etc. 



The coals in the United States are divided into : 



Anthracite, 



Semi- Anthracite, 



Bituminous, 



Cannel, and 



Bituminous Shale, J 



