Device for measuring radium emanations, preferably the emanation content of the soil air
DE415872C
Instrument for measuring all determinants of the earth's magnetic field
DE405202C
Device for the magnetic-mechanical testing of elongated, magnetizable bodies
DE421727C
Rotary balance
DE421899C
Method for the clear reproduction of magnetic field measurements
DE408640C
Circuit arrangement for testing changes in cross-section and quality in bodies of magnetizable material
DE405243C
Drilling device
DE411093C
Device to protect the torsion stressed axes in measuring instruments, especially for geomagnetic observations against rapid temperature fluctuations
DE400148C
Method for measuring alternating magnetic fields
DE398658C
Optical period analyzer
DE403702C
Device for the remote registration of seismographs and vibration meters
DE404098C
Method for determining the direction of electromagnetic radiation, preferably in mines
DE378224C
Device for determining the direction, intensity and polarization state of electrical waves, especially for earth exploration purposes in mines
DE418348C
Eoetvoessche rotary scale
DE406972C
Method for increasing the accuracy of the setting of a magnetic balance, as independently as possible of mechanical influences from cutting edge friction, etc.
DE380347C
Accelerometer
DE422348C
Procedure for the electrical investigation of the subsurface
DE389254C
Regulating device of drives for automatic writing devices
DE392987C
Device for searching for magnetic or electrically conductive materials
DE367634C
Non-polarizable electrode for earth exploration purposes
