The words âat least 17 years of age and *â*â* under 45 years of ageâ are substituted for the words âwho shall be more than seventeen years of age and *â*â* not more than forty-five years of ageâ.
Steel is cheaper, and brass is more expensive, and not much of a structural material. Brass is a tensile metal, and has a great ability to bend. It is used to make bearings, valves and moving parts, because it does not break easily. Steel, on the contrary, is difficult to cast, and quite difficult to work with in small machines.
Copper is a single metal, so every copper object has roughly the same properties. Brass, on the other hand, is an alloy of copper, zinc, and often other metals as well. The hundreds of different combinations means there is no single, foolproof way to identify all brass. That said, the color of the brass is usually distinct enough to separate it from copper.