Show will test device to detect earthquakes california scientists to try jap invention berkeley call calif f earthquake predicting devices which it Is hoped may enable scientists to foretell earth movements hours before they occur are being tested at the university universia sIt y of california patterned after a japanese invention the instruments are designed to measure infinitesimal tilting of the earths surface which japanese seismologists claim they have noted before earthquakes the devices have been installed near the hayward fault line siong along the lower slope of the berkeley hills since the instruments were installed there lime have been no movements of any magnitude along the fault prof byerly united states seismologist said and even if it should be proved that tilting Is a precursor of earthquakes years might be required to work out a technique of forecasting he believes some tilting has been observed on the instruments but it lias has been attributed tri buted to rains and consequent swelling and movement of the surface the instruments were designed by george E merritt Merrl tt formerly of the united states bureau of standards and were installed by the united states geodetic survey tilting Is detected by observing the movement of oil held in a bowl over whdeh a plate of glass Is suspended parallel to the oils surface if tilting occurs the surface of the oil ell is no longer parallel to the plate of glass even though this change may be too slight to be observed by the naked eye it ft can be determined by reflecting a beam of light simultaneously from the lower surface of the glass and the top surface of the oil when the two surfaces are exactly parallel the light Is reflected without interference but if the oil has moved in relation to the glass some of the light waves interfere with each other and a pattern Is formed |