Abstract: The invention is a process and device for performing successive drainage and imbibition phases of a first electrically-conducting fluid and a second fluid of lower density than the first fluid, in a porous sample (1) by means of a centrifuge. Each sample is placed in a main chamber (3) of an elongate vessel (2) fastened to the end of an arm of the centrifuge, together with a spacer (6) whose volume is so selected that, on the one hand, the interface between the two fluids does not come into contact with the sample in operation and, on the other hand, the volume of chamber (3) remaining free around the sample and the associated spacer is greater than, but preferably close to the pore volume of the sample, so as to maximize the displacement amplitude of the interface for a given variation of the volume of fluid displaced. A capacitive sonde (11) in an auxiliary cavity (4), connected to an outer measuring device, is used for measuring the displacements of the interface.

Abstract: The invention concerns a connection device for providing mechanical and electric connection between a multi-conductor cable and a well-probe, comprising a separation disk through which pass a plurality of pins, connected on the probe side to a female electric connector and at the opposite side to a hollow rods connected electrically to the conductors of the cable, an insulating sleeve having an end-piece for fixing the cable, inside which the connections of the rods to the conductors of the cable are made, the sleeve is fitted on the end of the probe body and is fixed thereto by a nut and a lock-nut providing, at the same time, sealed insulation between the inside of the body and the sleeve and interconnection of the electric conductors of the cable with those of the probe.

Abstract: A calibration system is provided for gas analyzers, and particularly for apparatus for measuring atmospheric pollution and for detecting gaseous pollutants. The device comprises a tight permeation chamber connected to a source of a gaseous pollutant or a plurality of chemically compatible gaseous pollutants, e.g., SO.sub.2, NO or CH.sub.4. A tube formed from a material which is permeable to the gaseous pollutant(s) extends across the chamber, one end of the tube being connected to a source of pressurized pure vector gas and the other end of the tube communicating with a mixer which is itself connected to a source of dilution zero air. Apparatus is also provided for regulating temperature to maintain a predetermined constant temperature within the permeation chamber.

Abstract: A ringing control device for a group of subscriber lines served by a connection network, comprising a relay for each line, the connection network providing a ringing control signal and a timing signal for controlling the relay, a ringing generator common to the group of lines and providing an A.C. ringing current to a line when the corresponding relay occupies a first position, a supervisory circuit for each line, connected thereto in the second position of the relay and delivering a signal to the connection network if the receiver is lifted while the relay occupies said second position, and a common off-hook condition detector delivering a signal if a D.C.