Electrical equipment used in reflection-seismograph prospecting

The reflection prospecting method measures depths to subsurface strata by recording the travel time of reflected sound waves. The acoustic energy of the sound wave is converted into electrical energy by a pickup, amplified, filtered, and recorded. The equipment described provides automatic gain control in the amplifier, filtering to eliminate frequencies outside the reflection spectrum, and means of recording reflections from several points on the earth´s surface, together with the necessary timing mechanism.