[21] Under the Spa Agreement (see Appendix No. 1) Germany was to be paid in cash 5 gold marks per ton for _all_ coal delivered, and, in the case of coal delivered _overland_, “lent” (_i.e._, advanced out of Reparation receipts) the difference between the German inland price and the British export price. At the date of the Spa Conference this difference was about 70s. per ton (100s. less 30s.), but this sum was not to be advanced in the case of the undetermined amount of coal delivered _by sea_. The advances were made by the Allies in the proportions, 61 per cent by France, 24 per cent by Great Britain, and 15 per cent by Belgium and Italy. [22] For details of these payments see p. 133. [23] This very valuable tax, first imposed in 1917, yielded in 1920–21 mks. 4½ milliards. [24] Dr. Wirth’s first Government prepared a Bill to raise the tax to 30 per cent, with power, however, to reduce the rate temporarily to 25 per cent. It was estimated that the 30 per cent tax would bring in a revenue of 9.2 milliard marks. [25] The same authority estimates that 85.6 of Upper Silesia’s zinc ore production and all the zinc smelting works fall to Poland. This is of some importance, since before the war Upper Silesia was responsible for 17 per cent of the total world production of zinc. Of the iron and steel production of the area 63 per cent falls to Poland. I am not in a position to check any of these figures. Some authorities ascribe a higher proportion of the coal to Poland. [26] These are the figures according to the Polish authorities. But it is difficult to obtain accurate pre–war figures for an area which was not coterminous with any then existing State; and these totals have been questioned in detail by Dr. W. Schotte. [27] See _e.g._, my controversy with M. Brenier in _The Times_. [28] In _The Economic Consequences of the Peace_, p. 92 _n._, I wrote as follows: “The reader must be reminded in particular that the above calculations take no account of the German production of lignite.... I am not competent to speak on the extent to which the loss of coal can be made good by the extended use of lignite or by economies in its present employment; but some authorities believe that Germany may obtain substantial compensation for her loss of coal by paying more attention to her deposits of lignite.” [29] That is to say, production in the middle of 1921 was at the rate of about 120,000,000 tons per annum. At that time the legal maximum price was 60 paper marks per ton (_i.e._, 5s. or less); so that the national _profit_ on the output in terms of money cannot have been a very material amount.