Abstract: A method is provided for detecting minerals and metal-containing materials which are located in sediment deposits on the sea floor and which exhibit an induced polarization response. In this method, a streamer cable is towed in the sea behind a ship. The cable has transmitters and receivers at the free end thereof and the cable is towed such that this free end is close to or trenches into the sea floor. The transmitters are used to transmit a square wave electrical current into the sediment of the sea floor while the receivers are used detect to any secondary signals produced by an induced polarization source located on or in the sea floor in response to the electrical current. The secondary signals are processed to determine measurement parameters characteristic of the source of the secondary signals so as to identify the source and using simultaneously acquired global positional data, to determine the location of the source.

Abstract: An encoding apparatus provides range or other data as determined by the setting of a control or selection knob therefor. The encoding apparatus is intended for use with an instrument providing an output voltage representative of data within a range, and providing output signals indicative of the setting for the range control or selection switch of the instrument. The encoding device is adapted to fit externally of the instrument chassis and is mounted between the range selecting knob and the chassis. The encoding apparatus is non-invasive, requiring no connection to or modification of the internal components of the measuring instrument.