A method of generating a gas commences by forming a solution in a reservoir. The solution is then fed through an electrolysis cell so as to liberate the gas from the solution. The mixture of the solution and gas discharged from the cell is heated by passing it through a heating tube. This causes it to self-circulate back to the reservoir by means of a thermosyphon effect. Finally, the liberated gas and the solution are passed through a gas separator to separate the gas from the solution prior to circulating the solution back to the reservoir. The gas generated by the method of the invention is typically a halogen, and in particular, chlorine, produced by the electrolysis of a brine solution. The apparatus of the invention is arranged for producing chlorine gas in accordance with the above method in a safe and effective manner without the need of costly circulation pumps.
