Copper Implements. 133 



must be made, generally in two or more parts. Pattern making 

 involves mucli knowledge and skill. 



I enumerate these difficulties in order to show that it was not 

 likely that a rude people possessed that amount of knowledge and 

 skill adequate to overcome these obstacles. 



I pass over all other modes of forming moulds, and speak only 

 of those formed in stone. Almost all savage tribes possess the 

 skill to fashion stone into various tools, and we are forced to ad- 

 mire the workmanship displayed in working the hardest materials, 

 such as flint, quartz, granite, greenstone, etc. In contemplating 

 these evidences of patient toil, we are assured that they could 

 readily work out suitable moulds in stone in which castings might 

 be made. 



Copper is a refractory metal, which melts at from 2200 to 2600 

 degrees, a temperature that can be reached only in a furnace, as- 

 sisted by some form of coal and an artificial blast. We must 

 have good evidence before we assert that these dwellers by the 

 lake possessed these indispensable auxiliaries to successful work- 

 ing in metals. " Copper, when melted, is thick and pasty, and 

 without the addition of some other metal, will not run into the 

 cavities and sinuosities of the mould." 



In consulting with an intelligent and skillful brass-founder, I 

 was shown a hammer weighing three pounds, cast of pure copper, 

 and was assured that this was the smallest casting he could make 

 of this metal. The addition of one pound of zinc to ten of cop- 

 per makes an alloy that will melt at less than half the tempera- 

 ture of copper, and will flow freely. 



In casting in copper it is positively necessary to put the ma- 

 terials in a crucible, and that the surface of the melting mass be 

 covered with a flux in order to effectually defend the melting 

 metal from the action of the atmosphere. 



A word about crucibles. The manufacturing of good crucibles, 

 such as will withstand the heat necessary to melt the more re- 

 fractory metals, involves such a degree of knowledge, that for 

 many generations the entire civilized world was dependent on a 

 small section of Germany ; and even now Hessian crucibles are 

 unsurpassed. In England there are now several manufactories 



