Abstract: A process to detect toxic ions in the atmosphere or dissolved in water with n electrochemical cell which comprises an active electrode, a reference electrode and a counter electrode, connected by an electrolyte and to which a voltage is applied.The voltage alternates on each side of the thermodynamic potential. The cell, which is adapted to detect toxic gases in air, comprises a condensation chamber connected to a venturi for the admission of air and electrolyte, and to a measurement chamber. The electrolyte carrying the dissolved toxic gas is condensed in this chamber prior to passing through the measurement chamber.The invention is applicable in particular to check the atmosphere of workshops, and to check the pollution of bodies of water with an independent portable unit.

Abstract: An air lock in accordance with the invention is composed of two portions -- stationary hemispherical bell 6 fastened on a submarine rescue device 5 and a swivel skirt 7 in the form of a portion of a swivel joint, nested in the bell with a slight amount of play, bearing a peripheral sealing joint 28 which is applied against the hull 2 of a submarine around an opening 3. Two sealing joints 19 and 15 are placed between the bell and the skirt and the intermediate space 20 is filled with oil maintained at a constant pressure which is slightly different from the hydrostatic pressure.