They require extra care when transporting. If hung on a wall it is strongly recommended that they be protected from outside influences. Pencil - It consists of a rod of marking substance, such as graphite, enclosed in a wood casting. Pencil, as we know it today, was born in the end of 18th century. Allowing for exact, linear strokes it quickly became very popular.
Pencils can range in their hardness, which is related to proportion of graphite to clay in the lead.
Harder pencils are generally used for drafting. One of the most insightful 19th century users of graphite pencil was French artist named Edgar Degas. Bronze - This is an alloy of copper, tin and, sometimes small amounts of other metals. It was first used 3000B.C. Until the discovery or iron, bronze was primarily utilized for creation of weapons. It is a rather popular medium for sculpture.