For Reference

For long men thought the earth was flat. In the latter part of the 15th Century, the idea began to get about that the earth was a sphere.

As early as 1696, it was shown that the earth is not a true sphere. Various calculations have since been made of the earth's shape and dimensions.

Last week, it was announced that there finally had been an international agreement on this subject. The International Geodetic and Physical Union, meeting at Madrid, Spain, adopted the figures of Director John F. Hayford of the College of Engineering of Northwestern University, noted for his demonstration of the theory of isostasy, fundamental concept of the reciprocal balance of segments of the earth. By investigations made in 1909 and 1910, he determined that the diameter of the earth at the equator is 7,926,678 miles and 7,889,964 miles through the poles. This establishes that the earth is not a sphere but an ellipsoid, slightly flattened at the poles. The Hayford figures have now been adopted as the "ellipsoid of reference," and the geodetic authorities of all the nations will use them to coordinate their work. Director Hayford was, at the time of this decision, seriously ill at his home in Evanston. A few days later, he died.