Abstract: An independent vehicle suspension in which the height change which can be made while the vehicle is stationary is limited so as to prevent the system from having to make too great an associated track change. This prevents the system from becoming locked during a height change due to stiction between the wheels and ground which opposes the track change. The height change is completed when the vehicle is detected as starting to move.

Abstract: A motor vehicle suspension system includes rear suspension units to adjust ride height between sprung and unsprung parts of the vehicle, control means for monitoring and maintaining ride height at a particular setting and wheel speed monitoring means for monitoring wheel speeds. The control means provides a corrective up height change signal in the event of an unrequested height change and there existed before the unrequested height change a wheel speed signal indicative of vehicle movement. The corrective height change signal may be applied to each suspension unit or the control means may monitor abnormal vehicle activity and provide the corrective height change signal to the appropriate suspension unit. One example of abnormal vehicle activity is when the wheel speeds differ significantly, the control means responding to provide the corrective height change signal to the suspensions unit on the side of the vehicle with the highest wheel speed.

Abstract: Gas purification processes for removing hydrogen sulphide (H.sub.2 S) from a foul gas stream, such as coal carbonization gases, involving a circulating liquid reagent in which the H.sub.2 S is absorbed and converted to sulphur which is recovered and the reagent regenerated and recycled exhibit progressive deterioration of the circulating reagent due to contamination by process by-products. The invention provides a method of decontaminating such a circulating reagent by subjecting a bled-off sidestream to high temperature hydrolysis, so producing gaseous products recyclable to the foul gas stream. Solid products may also be produced which may be recycled to the reagent, perhaps after high-temperature reduction.