Hundreds and thousands of blast furnaces produce steel and iron all over the world. Economists of different countries scrupulously calculate how many million tons of metal were put out this year and predict the amount to be smelted next year.

    And the same economists inform us of the astounding fact that every eighth blast furnace operates in vain. Each year about 12 per cent of the metal produced is ingloriously lost to mankind, falls victim to a merciless enemy. . .

    The name of this enemy is simply rust. Science calls it metal corrosion.

    Not only iron and steel perish but the nonferrous metals copper, tin and zinc too.

    Corrosion means oxidation of metals. Most of them are not very stable in the free state. And even in the air the lustrous surface of a metallic article becomes coated after some time with ominous varicoloured oxide patterns.
 

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