An Electrical Conductor of Sodium.--The members of the American Electrochemical Society meeting at Cleveland, O., were told about a conductor of metallic sodium, four inches in diameter, that is being used to carry as much as 4,000 amperes of electric current. Readers acquainted with the properties of sodium will realize there is something wrong with this picture.--It should have been added that the sodium was enclosed in an iron pipe. Sodium, left in contact with the atmosphere, widely combines with oxygen, moisture and carbon dioxide to give caustic soda and sodium carbonate. Placed in water, this active element rapidly generates hydrogen and sufficient heat to combine the latter with oxygen with explosive force.
Although the resistance of sodium is three times that of copper, it weighs only one-ninth as much. To carry the same amount of current, a sodium conductor must have almost three times the crosssectional area as one of copper.
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Pine or Hickory for Fuel? (U. S. D. A. Clip Sheet No. 744).--Pound for pound, pine wood gives off more heat than hickory. But, since wood is purchased by the cord (volume), rather than by weight, a cord of hickory probably will furnish the more heat. And so we are right back where we started.
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