A new vertical seismograph

The vertica1 seismograph herein described makes use of a mechanical system of short period in combination with an electro-mechanical transducer of high sensitivity coupled to a recording galvanometer. In the Galitzin seismograph the transducer consists of a coil which moves in a magnetic field in such a manner as to generate electromotive force proportional to the velocity of the inertia reactor. The present transducer embodies a modification of the common telephone receiver principle and is also of the velocity type.