Science: For Rainy Days

One way to make a raincoat is to use a solid sheet of rubber or plastic that water cannot penetrate. Another and newer way is to cover the fibers of ordinary cloth with a substance that water does not "wet." Many substances have this property, e.g., the oil that waterproofs a duck's feathers. But most of them are unsatisfactory; they wear off or are easily removed by cleaning processes. The current house organ of the Dow Chemical Co. tells about waterproofing agents made of silicones: organic compounds with atoms of silicon built into their molecules.

When a drop of water hits unprotected...

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