RUELLE, Opérations des Changes des principales places de l'Europe, 1775

Second edition.
The complexity of calculating currency exchanges between all the currencies of Europe, each based on a non-decimal system.
There is also a table of changes (evaluation of the French currency in different places).
"You will find, at the end of this work, the evaluation in silver of France of the gold and silver coins of the different places of Europe, according to authentic tests". (excerpt from the preface)
It will be necessary to wait until 1866 for the establishment of a gold standard which will simplify international exchanges.