National Geographic : 1947 Mar
The National Geographic Magazine Telephone Pole Diseases Get Expert Study in Bell Laboratories' "Clinic" Test poles, left to right, have been damaged by fungus, a woodpecker, carpenter ants, and rot caused by fungus. Scientist is removing spore-bearing organs of the fungus for study to find a method of protecting poles. SNational e ;galhic Sioe' ty Ekt 111mls \ \VYillard It. ('ulver 50,000 Coal Granules, Used in Every Telephone, Cover Only a Playing Card Spot Tiny, specially treated particles, crushed from anthracite like the lump at right, conduct electricity and trans late voice vibrations into electric waves on wires. Granules are held in transmitter in container in girl's hand.