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.