100 Years Ago

摘要

The metals occurring most frequently are gold and copper. The former is much more widely distributed than the latter, and must have been the first metal to be known in many regions. It is, however, one of the most worthless metals for practical purposes, so that until the rise of Greek and Roman civilisation but little use was made of it. Copper, too, we only find in use to a very limited extent, as it was not well suited for the construction of weapons or useful implements. On the other hand, its alloy with tin afforded a metal which in many physical properties could only be surpassed by iron or steel.