Fifty-Year Trend of World Mineral Production

HOW have recent events affected the general trend in world mineral production? What effect has the World War, with its resultant boom and depression, had on the long-term trend of output? Have all of the principal metals and fuels been similarly affected, or have some boomed or slumped much more than others? The trend of world production of coal, iron, the principal nonferrous metals, and petroleum is shown in the accompanying chart, covering the period from 1882 to 1931 inclusive-the last fifty years. The curves are plotted logarithmically to show the comparative trends. In the lower left-hand corner of the chart is a slope diagram to aid in visually evaluating. the average yearly rate of increase in production; from this one can easily see, for example, that the petroleum production curve indicates an average annual increase of around 8 per cent, and that up to the period of the World War the average annual increase in copper production was about 6 per cent.