EARTHQUAKES OF 1928

Whenever the earth trembles in any part of the world, the first thing the public generally learns, through the daily press, is that some seismograph station has recorded an earthquake at a certain distance. Sometimes the report might say that it appears to be in a certain general direction. A few hours later, the papers carry a further report—that, with the aid of data gathered by Science Service by telegraph from perhaps a dozen or more different stations, sometimes as far separated as Manila, Sitka, Washington, and San Juan, the U.S. Coast and Geodetic Survey has located the exact center of the quake. Perhaps, as in the case of one famous earthquake a few years ago, in the Kansu province of China, many months may elapse before actual reports from the damaged area reach civilization, though the earthquake itself sent its own message that enabled the experts to locate it within a few hours.

The map on the cover shows some of the most important earthquakes thus located during 1928, with the cooperation of Science Service, the U.S. Coast and Geodetic Survey, the U.S. Jesuit Seismological Association, whose stations, at various Jesuit colleges, are among the best in the world. The black dots indicate the location of the quakes.

5,000,000 VOLT ARTIFICIAL LIGHTNING

Artificial lightning of 5,000,000 volts is now produced in the experimental lightning laboratory of the General Electric Company at Pittsfield, Mass., F.W. Peek, consulting engineer, told the American Institute of Electrical Engineers.

The previous record was 3,600,000 volts, but higher voltages are now obtained by the use of a radically new method which, in effect, throws into series four or more of the smaller lightning generators.

ECHO TELLS POSITION

Methods of locating a ship's position by means of automatic radio signals sent out from shore stations upon the receipt of a sound signal through the water from the ship have now reach a high degree of perfection and dependability. This is the announcement made by Col. E. Lester Jones, director of the U.S. Coast and Geodetic Survey, in his annual report.

Depth measurements are made by the survey's ships with the echo sounding device. A sound wave travels to the bottom, is reflected back and the time taken indicates the depth. In order properly to locate the position, however, it is necessary to know the position with respect to fixed points that can be identified on maps. With radio this can be done at night or in cloudy weather.

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