Platinum

A metal; one of the elements; symbol, Pt; atomic weight, 197.4; equivalent, 49.35; valency, 4; specific gravity, 21.5. It is a conductor of electricity. The following data refer to the annealed metal at 0° C. (32° F.)   Relative Resistance (Silver annealed = 1),   6.022   Specific Resistance,   9.057   microhms.   Resistance of a wire,   (a) 1 foot long, weighing 1 grain, 2.779   ohms.   (b) 1 foot long, 1/1000 inch thick, 54.49     "   (c) 1 meter long, weighing 1 gram, 1.938    "   (d) 1 meter long, 1 millimeter thick, .1153   " Resistance of a 1 inch cube,   3.565 Electro-chemical equivalent (Hydrogen =.0105),   0.5181. The coefficient of expansion by heat is almost the same as that of gla . It can be pa ed through holes in gla and the latter can be melted about it so as to hermetically seal its place of pa age through the gla . It is used in incandescent lamps for leading-in wires and other similar uses.