While the design and manufacture of the medium tank designs had been taking place, numerous other projects connected with armoured vehicles and their equipment had been under consideration. Some proved to be very short-lived; for example, a small remotely-controlled electric tracked-vehicle (1.5 metres long), packed with 70 kilograms of explosive was examined in the summer of 1916.1 The intention was to drive this into an enemy position and then detonate the charge but the prototype failed at the first set of tests, as it could not climb a mild slope. The idea was abandoned, only to be revisited rather more successfully by the Germans in the next world war with their Goliath demolition vehicle. Of rather greater potential were the investigations into giving the tanks some form of smokegenerating capability. It proved difficult to find ways to do this efficiently and the main line of research used sulphuric acid to generate the smoke. This was tested using modified light tanks and was of limited success.2 Provided that the humidity was low and there was little wind, the smoke generators could cover a couple of tanks from all observation relatively quickly. The drawbacks were that smoke could only be generated for a couple of minutes and there were obvious dangers in transporting sulphuric acid around a battlefield, so this idea was abandoned, leaving smoke cover for the tanks to the artillery. However, there were two areas that received most attention and activity, the heavy tanks and the light tanks. The heavy tank projects consumed both resources and much attention but failed to get any heavy tanks on the battlefield during the war. By contrast, the revolutionary light tank design was to prove an important component of the success of the AS and it will therefore receive more attention in this chapter.