Let us now convert these aces into troy grains, according to the proportion established between Dutch aces and troy grains, in the last chapter of the third book. The equation will stand thus, 5192.8 aces, being equal to 3840 troy-grains, 683.2 aces, therefore, will equal 505.21 troy-grains; which, consequently, is the weight of a ducatoon, or of 3 florins bank money of Amsterdam. Next as to the fineness of this coin: The ducatoon was coined, according to the imperial standard, of 14 loots 16 grains fine: that is to say, it is 268⁄288 parts fine, and 20⁄288 parts alloy. To find, therefore, the number of Hollands aces, and of troy grains of fine silver in the ducatoon, state the two following proportions: 288 : 268 :: 683.25 : 635.75 aces fine. 288 : 268 :: 505.21 : 470.13 troy-grains fine. In the last place, if we divide the number of aces, and troy grains fine in the ducatoon, by 3, we shall see the exact weight of fine silver in 1 florin of Amsterdam bank money. 635.75⁄3 = 211.91 aces, and 470.13⁄3 = 156.71 troy-grains fine. These calculations premised, it would be an easy thing to fix the exact par of the metals, between sterling and bank money of Amsterdam, were the British coin of legal weight, and were the metals there rightly proportioned. But is it to be supposed, that any person who has bank money of Amsterdam, would exchange, at the par of the metals, with sterling silver, which is many _per cent._ too light, or against English bank notes paid in gold, always overrated with regard to the silver, and often too light also? While, therefore, the coin of Great Britain stands upon the present footing, all calculations of the par of exchange, as it is commonly computed, upon the intrinsic value of the coins of other nations, must be delusive and of no utility whatever. For the sake of giving an example, however, here is the real par of the two currencies, upon silver sterling coin of full weight. One pound sterling should contain, as has been said, of fine silver 1718.7 troy grains, and contains 240 pence sterling: state, therefore, the following proportion, and you will find how many pence sterling one florin of Amsterdam banco should be worth. 1718.7 : 240 :: 156.71 : 21.883. Thus 21.883 pence sterling is exactly the real par of an Amsterdam florin banco, supposing sterling money to be silver, at the full weight. The florin bank money being regulated upon the ducatoon, an old species not now coined, the fineness of the silver was determined; and the weight of the 200 ducatoons being determined also, this regulation determined the weight of single pieces, and fixed the standard of the florin banco, in weight and fineness. The current money in Holland, coined by the state, is the florin of 200.21 aces fine, as we have seen in the last chapter of the preceding book.