§ Viscount Wolmerasked the Secretary for Mines whether he can state the approximate price in London in July, 1923, August, 1932, and to-day, of coal answering the following description: untreated bituminous slacks, small and or duff, with a calorific value of about 7,000 calories, moisture content as low as possible, and ash content about 12 per cent. 14 per cent. of the dry coal?