French revolutionary calendar calculator
Other mathematicians adopted the decimal fractions. As well as explaining decimal arithmetic, Stevin advocated the decimal division of weights, measures and currency ( 3). His book was soon translated into French, with an English translation, “Disme: The Art of Tenths”, appearing in 1608. Arabic numerals became common about 1500, but it was not until 1585 that Simon Stevin, a Flemish mathematician showed in his book, “De Thiende”, how fractions could be expressed in Arabic numerals using a decimal point. However, this had become possible only in the late Middle Ages, after ‘Arabic’ numerals, probably of Indian origin, began to replace Roman numbers. When the metric system was first introduced all units were divided decimally, making calculation easier. This situation caused difficulties for internal and international commerce, made worse by the need to calculate in twelfths, sixteenths or other fractions when converting from one system to another. In Britain most standards had been fixed nationally since the sixteenth century, but in France there were many local variations. However units with the same name varied in size from country to country: for example, the French pound and foot were each larger than their British equivalents. The unit of length was the foot of 12 inches, each divided into 12 lines, though for many purposes a longer unit was preferred – such as the French toise of 6 feet or the British yard of 3 feet. The standard weight was the pound of 16 (sometimes 12) ounces which in France was divided further into 8 gros, each of 72 grains. Before the Revolution in 1789, France, like most European countries, used weights and measures derived from those of the Romans.