Gas generating apparatus
Gas generating apparatus comprises an electrochemical cell having gas generating (2) and counter electrodes (3) with an intervening body of electrolyte (9). Current passing between the electrodes causes the generation of gas at the gas generating electrode. A first membrane (24) permeable to gas but substantially impermeable to the electrolyte is positioned sufficiently close to the gas generating electrode (2) that gas generated by the gas generating electrode diffuses through the electrolyte and out through the membrane under the influence of a gas concentration gradient, substantially without forming bubbles in the electrolyte and irrespective of the orientation of the apparatus.