THE BEGINNINGS OF METALLURGY. 87 



and sawing of stones do not necessarily require metallic tools, but 

 were all formerly done with instruments of stone and wood. 



It was believed a little while ago that the stone age was superseded 

 by a bronze age. A closer examination of the subject has made it 

 clear that we have in this case to deal not with sharply distinguished 

 intervals, but wuth different degrees and conditions of civilization, 

 which existed at the same time among different nations, and even 

 among different classes of the same nation. Stone tools and weapons 

 were still in use in Northern Europe long after the hard metals had 

 become common in the South ; but even in Southern Europe the poorer 

 classes continued to use stone implements till late in historical times. 



Survivals of stone-age civilization are now met with among only a 

 few peoples ; men have as a rule advanced to the metal-using stage, 

 which has acquired its significance in consequence of the production 

 of the hard metals. It is our purpose to review the origin, the ac- 

 quisition, and the application of these important materials. 



I have already spoken of the core of the earth as consisting chiefly 

 of iron, while the crust is composed of eruptive silicates. The fluid 

 from which these masses have been derived is a mixture of several 

 combinations, the principal elements of which are oxygen, silicon, the 

 lighter earth and alkali metals, and the heavier metal, iron. Oxygen 

 predominates, and is combined with the other elements into stony 

 oxides. The excess of oxygen floats around the oxidized dead-burned 

 globe as life-air. I have mentioned only iron among the heavy metals 

 important in civilization because it is the one that plays the most im- 

 portant part in the composition of the rocks. We also find smaller 

 masses of other heavy metals in the primitive matter of the earth. 

 Most of them appear sparsely distributed in the eruptive rocks in com- 

 bination with sulphur, but a few occur in oxides. Besides these we 

 also find ores concentrated in crevices and in pockets in rock-masses 

 of different kinds, where they have been carried in aqueous solution. 

 These local accumulations of ores first made it possible for men to 

 obtain the rarer metals in masses and apply them to use. The metal- 

 lic sulphurets nearer to the surface have been changed by atmospheric 

 action partly into the simple metals, partly into oxides. This was a 

 fact of great importance in the beginnings of metallurgic art ; for the 

 oxides are much easier to reduce to the condition of pure metal than 

 the sulphurets. The unmixed metals — the precious metals and copper 

 — are, of course, immediately available, and can be brought into any 

 form that may be desired by hammering or casting. But little advan- 

 tage was, however, derived from this circumstance. The first decisive 

 step was not made till the hard metals, bronze and iron, were pro- 

 duced. These substances could not, however, be obtained at once, for 

 neither the tin required for the manufacture of bronze nor iron in the 

 metallic state was at hand ; and it was a great step when the thought 

 first occurred to man of separating the metallic elements from their 



