J C WILSON of the University of Denver has found that the first and only commercially run supersonic airliner - the Concorde - emits loads of sulphur particles in the atmosphere. He says that the discovery may compel engineers to alter the design of the engine and the fuels to be used in a fleet of supersonic aircraft5 which is being considered for commercial launching by the industry and NASA. A study the Concorde, to measure and determine the chemicals dumped in the stratosphere by any supersonic jet engine aeroplane flying over 50,000 ft revealed this. Wilson observed that the nitrogen oxide reactions measured in the test were quite as expected. But the sulphur contained in the jet fuel exhaust clensifies into particles in no time at all. He felt that the particles could enhance the depletion in the ozone layer, following a chemical reaction.