That the surface of the earth itself may be subject to tides like those of the ocean has long seemed probable,* but there has been no tidal gauge to measure these heavings accurately. At the University of Texas last fortnight a gravitimeter was announced which indicates a daily tidal movement of the solid earth at Austin amounting to two or three incheslarger than ever suspected.
The instrument, a refinement of the commercial gravitimeter used in locating oilfields, is a strong spring with a weight attached to its lower end. Any change in the...
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