A calculation of foreign exchanges, [electronic resource] : as transacted on the Royal Exchange of London: or, tables, shewing at once, or by a few additions, any sum of English money reduced into foreign species, and likewise any Sum of Foreign Species reduced into English Money, by Way of Exchange, at the several Prices, as from Time to Time the Exchange may Rise or Fall. By Edward Oldenburgh, merchant. The third edition. Calculated for the present Course of Exchange; with some New Tables. With several additions prefixed to each particular Table, shewing how Books and Accounts are kept at each Place; and likewise in what Money Exchanges are usually drawn, Real as well as Imaginary; with the Method how to make the Operation, by The Rule of Three, in the plainest and most concise Manner. By the same Hand.