That the best method of determining exactly the true and intrinsic value of the metals, coin, or money, in which the balance due to or from a foreign nation is to be paid, is to compare the respective value of fine bullion with the respective denominations of the coin in the one and the other; and to state the difference as the price paid for the exchange[20]. Footnote 20: There occurs another considerable difficulty to be removed, before the real par of exchange can be exactly determined from the price of bullion, to wit, the uncertainty of weights, and the multiplicity of them. Every nation in Europe has a different weight, I might almost say every city. This has proceeded, in a great measure, from the inaccuracy with which they have been made formerly. I think it is highly probable, that many, at least, of the principal weights in Europe, have derived their origin from the same standard; although they are now considerably different. Those I am best acquainted with are the following, of which I shall here set down a short table, reduced to troy grains, according to the best calculation I have been able to make. One ounce troy contains 480 troy grains. One ounce Paris, or _poids de marc_, 473 One ounce Holland troes 473.27 One ounce Colonia 449.33 These are the weights used in the mints of England, France, Holland, and Germany. If therefore we should call the troy ounce 100, the proportion of the rest will be as follows: Troy 100 Paris 98.541 Holland 98.597 Colonia 93.61 I have chosen to reduce to ounces; because it is the denomination in which the proportion of weights is best preserved. These ounces I apprehend to have been originally taken from the old Roman pound, which was the weight adopted by the Emperor Charles the Great, who applied himself much to the establishing a general standard of weights in his dominions. In the examples I have given, we see how the Colonia ounce deviates more than any other from the average on the whole. This ounce is very near equal to the old Saxon ounce, established in the English mint at the Norman conquest, and there preserved, until Henry VIII. substituted in its place, the troy weight. This circumstance makes it probable that the Saxon ounce came originally from Charles the Great, who first conquered the Saxon nation, and drew them from a state of absolute barbarity. The rude manners of the Saxons may have occasioned this great deviation. The difference, therefore, in those ounces, I ascribe to the progressive error of those who have made weights, and from the neglect of preserving a proper standard.