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ANTHROPOLOGY: W. HOUGH 
The knowledge of metals in the Bronze Age was confined to those 
native metals, copper, gold, and silver, and of reduced metals tin and 
possibly lead. The development of temperature in the Bronze Age 
paved the way for the reduction of iron, the most important metal 
known to man. 
In general no extensive reduction of ores could be attained with the 
facilities of the Bronze Age. It is improbable that much copper ore was 
reduced in this age, the source of supply being nuggets of native copper. 
Tin in the form of the oxide resembles a native metal and would at- 
tract the attention of man. It is easily reduced at a moderate heat and 
requires no roasting or flux, but whether this had any bearing on the dis- 
covery of bronze is not clear. The combination of copper and tin pre- 
sents no difficulties since both metals are easily accessible and of wide 
occurrence. Native copper containing tin and forming a natural bronze 
is known, but is rare and had no effect on the discovery of alloys. Cop- 
per alone is very difficult to smelt and cast so that there is no very defi- 
nite copper age and not many cast artifacts of this metal have been 
found. The copper age would be the period when native copper was 
shaped by hammering as especially in North America. Bronze may 
have resulted from experiments with mixtures of various substances to 
lower the melting point and to admit of casting in a closed mould. As a 
rule ores consisting of oxides of metals presented little difficulty in smelt- 
ing. Carbonate ores could be oxidized by roasting before smelting fol- 
lowing the old process. The chief difficulty in the reduction of ores 
is due to the presence of impurities chiefly sulphur and phosphorus 
which remain the bane of modern metallurgists. Another difficulty is 
the kind and proportion of flux. The question of fuel was not pressing, 
charcoal being the usual and immemorial supply up to the use of coal. 
The niceties of the reduction of ores remained for modern science, 
early metal workers confining their attention to varieties which could be 
reduced by the facilities and knowledge in their possession. It is pos- 
sible that the bronze age even at its focus may have overlapped the 
iron age and it is not strange that some students should have been led 
to assert that iron preceded bronze. The accumulated knowledge re- 
quired for the reduction of an inconspicuous ore to secure a metal not 
known in a free state and with properties and value unknown is greater 
than the production of an alloy of two metals one free and the other 
practically free and both known to man for untold generations. There 
are also the high temperature, 1200-1300°C., and the experimental 
data on fluxes required in the reduction of iron ore. The metallurgy of 
iron was a distinct advance on that of bronze and made use of the ex- 
