A Description in non-technical Language of the diverse and wonderful ways in which chemical forces are at work and of their manifold application in modern life.
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By permission of Robertson Electric Lamps, Ltd.
Sealing Platinum Wires into an Electric Glow Lamp
Platinum expands on heating and contracts on cooling at the same rate as glass. Hence if
• he wires are sealed into the fused glass at a high temperature, the joint is still tight after cool-
ing, and the glass is not strained as it would be if the rates of contraction were different.