IN view of the importance of national economy in our fuel reserves, it is not surprising to find that Sir Dugald Clerk selected the subject of the conservation of fuel in the United Kingdom for the James Forrest lecture which he delivered at the Institution of Civil Engineers on April 20. The coal raised in 1913 was about 287.4 million tons, of which 189 million tons were retained and consumed here. The total coal reserves at 2 per cent. per annum increase will be exhausted in about 250 years, but fuel will be so expensive long before that time has elapsed that we shall be hard pressed to maintain the existing population. A return to the agricultural civilisation of 1750 would require the reduction of our population to one-third. It is of the utmost importance to study the engineering problems arising.