THE internal combustion engine began with gas as fuel, but the use of concentrated liquid fuel has determined its vast development in all fields of transport. Circumstances, too familiar to mention, have in recent years caused a renewed attention to the possibilities of reverting, in part at least, to the use of gaseous fuel from coal and even coal itself. In Continental countries this has been encouraged by fiscal and other forms of State aid. On March 27–28, the Institution of Mechanical Engineers held a conference at Swansea, when the position of the subject was reviewed. It was reported that in 1938 a producer-fed passenger bus had maintained for one year a regular service from Inverness covering 32,000 miles. Its fuel cost was £90-as against £253 for petrol and £136 for oil. There was a charge for cleaning and attention of £30. In all producer-fed vehicles one must reckon on a 30 per cent loss of power owing to extra weight and cost due to the producer. On the Continent there are many gas-engined small vessels fed by producer gas. The position attained by engines fed by compressed gas was reviewed and it was considered that engines using injected fuel with high compression ratios will give performances equal to those of compression ignition engines operated with fuel oil. Progress with road vehicles has been determined by the use of thin walled containers of alloy steel capable of working at 3,500 Ib. pressure. Dr. H. Wahl gave an optimistic account of the position and future of an engine running on coal dust.