PLATINUM.
Platinum is a metal of a white color, and is the heaviest substance known, being more than twenty-one times heavier than water. It is capable of being welded and wrought out by the hammer like iron; it is not acted on by any of the acids, but, like Gold, is dissolved by chlorine or a mixture of hydrochloric and nitric acid; it does not tarnish by exposure to air, and is extremely difficult to melt, requiring the very highest heat that can be produced; these qualities render it one of the most useful of the metals to the chemist, furnishing him with retorts, crucibles, and evaporating dishes suitable for many purposes; its high price, however, renders it not so generally used as it would otherwise be.