gravels of rivers,
where, as we have already mentioned, primitive men must have, at a
very early date, sought for gold. Owing to their weight, the gravel
of tin-stone would remain behind with the gold when it was washed. "In
process of time its real nature might have been revealed by accident;
and, before the eye of the astonished beholder, the dull stone, flung
into the fire, became transfigured into the glittering metal."<8>

When two metals come together in a molten state, they often form, not
a mixture of the two, part copper and part tin, for example, but a
new compound, different from either, called an alloy. Copper is, so
to speak, a sociable metal, and readily unites with many different
metals--amongst others with tin, when it forms bronze, the article that
marks a new state in the history of primitive culture. It seems to us
strange that an alloy, a combination of two different metals, should
have been the first used by man, and not a simple metal like iron. Such,
however, is the fact of the case; and we have tried to point out the
probable steps which led up to the invention of bronze. We can scarcely
comprehend the difficulties which attended the labors of the primitive
metal-workers. There were no books containing the wisdom of many, from
which the investigator could draw his stores of knowledge. and the only
way that knowledge could be disseminated was by word of mouth.

Now, when one man makes an important step in a discovery, hundreds of
earnest workers, some, perhaps, in distant places, are quickly made
aware of the fact, and extend its scope, or point out its imperfections,
and thus hasten on the desired end. Then, each individual, or community,
must, of necessity, have commenced at the beginning, and the discoveries
made would hardly be perpetuated in the memory of others. There were
so many obstacles to be overcome before a knowledge of bronze could be
acquired, in the then existing state of human knowledge, that it must
ever remain a source of wonder to us, at the present day, that it was
invented at all.

We may picture to ourselves the ancient copper-worker, after numerous
experiments, guided by some good genius, finally hitting on some process
by which, from his mass of ore, he extracted a nearly pure piece of
copper. Having learned how to reduce these ores, there are many ways in
which it might have been found that a mixture of the two metals would
form a new compound of greatly increased value