RELATIONS OF MINING ENGINEERING 635 



The miner, pushed by his metallurgical partner, soon got to the 

 end of the loose ore lying on the surface and began breaking it 

 from the ledges with his stone hammers. He found that by heat- 

 ing the ore and quenching it with water it would crumble more 

 easily. In faofc, this was probably the chief method of mining for 

 many centuries. 



A mine at this period may have been a pit or trench twenty feet 

 deep, more or less, from which the ore and water were carried out 

 on men's backs, using a tree with stubs of branches for a ladder. 



In time the metallurgist found that by manipulating his iron in 

 connection with carbon he could harden it and that the hardness 

 was greatly augmented by quenching it in water. He had made 

 the discovery of steel and of tempering. 



The miner asked for a better hammer and got one of steel and 

 with it the "point" which by blows of the hammer chips and severs 

 the ore from the ledge. The hammer and point, "Schlegel und 

 Eisen," must have been the standard mining tools for many cen- 

 turies. 



The primitive American mined copper at least 500 years before the 

 discovery of this country by Europeans (Egleston). This is indicated 

 by counting the rings in tree-trunks growing in their old workings. 

 They mined the copper with stone hammers, heating the rock with 

 fire to make it more friable. They mined to a depth of twenty or 

 thirty feet, but rarely went underground; used wooden shovels to 

 move the rock and wooden bowls and bark troughs to dispose of the 

 water. They did not want and could not use pieces of copper larger 

 than a few pounds, which they took as they found them, beat out 

 cold into shapes, leaving the silver attached to the copper. They 

 apparently had no knowledge of concentration or of smelting. 

 They used the copper for tools of the household, of the shop, of the 

 chase, and of war, as well as for decorative purposes. 



The making of iron tools enabled the miner to penetrate into the 

 ground. He devised ropes, buckets, and a rude windlass for lifting 

 out ore and water. His roof and walls of rock began to fall in on him 

 and it was necessary to bring in timber props and to leave pillars of 

 ore to hold the walls apart. 



About this time the horse-windlass and a better quality of rope 

 must have been designed for hoisting from greater depths. Mines at 

 this time may have reached a depth of hundreds of feet with tunnels 

 and galleries though small in size, yet cut out with a care and finish 

 almost like that of the stonemason's work on public buildings. Such 

 tunnels of three hundred years ago can be seen to-day in the German 

 mines. 



The metallurgist asked for cleaner ore, free from earthy and 

 siliceous impurities which hindered or prevented his smelting opera- 



