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 and the. proportions of these two metals are varied to produce brass having different properties. 3. Distinguish between a pure substance and a heterogeneous mixture at (a) the macroscopic. level and (b) at the microscopic level. Solution.