_Tin_ was early known in the Orient, being one of the imports of Egypt from Spain, through the Phoenician merchants, who also obtained it from Britain. It was one of the principal commodities in the marts of Tyre, and was used as an alloy with other metals. _Gold_ and _silver_, the precious metals, are mentioned in the earliest times and were highly esteemed; they were utilized in the manufacture of articles for domestic use, for personal adornment, and for ceremonial accessories. These metals were obtained by the Hebrews from Arabia, Ethiopia, Egypt, and Spain. Gold was used as a medium of exchange, like money, as early as the time of Abraham, but was then weighed, not counted. Silver was profusely used at that time in the East, and seems to have been very abundant in the time of Solomon. An alloy of gold and silver, called _electrum_, was also used. _Zinc_ was discovered in 1520 by Paracelsus, an alchemist and astrologer of Europe, and was immediately adopted as a valuable alloy. _Bronze_, a composition of copper and tin, seems to have been much used in Europe before the adoption of iron for the same purposes, as Roman remains testify; this was probably due to its greater ease in working. _Brass_, a composition of copper and zinc, soon became popular, owing to its being more easily worked than bronze. _Burnished brass_ is mentioned in Ezekiel, but is considered to have been an alloy of copper, there being a white metal, greatly used for ornaments in the East, called _white copper_. Locks and contrivances to secure protection and privacy were originally made of wood, and a wooden lock (the oldest yet discovered) was actually found in the ruins of Nineveh. This lock appears to have been used on a gate of an apartment in one of the palaces of Khorsabad. The ancient Egyptians constructed locks and keys from brass and iron, thus showing their creative mechanical skill, while the ornaments discovered in the royal tombs display the high order of their art. The Greeks and Romans were skilled workers in the metals, and many beautiful examples remain to attest their ability and ingenuity.