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.
Brass is an alloy of copper and zinc. Copper cannot be usefully anodized. Zinc can be anodized but only at very high voltages (hundreds of volts). My understanding is that brass cannot be anodized. Letter 1785 alludes to an historical oxidized finish for brass without making any claim, though, that electricity has anything to do with it.