for many discoveries and inventions. He was a pioneer of the development and the practical application of (engineering related) science such as mathematics, physics and applied science like hydraulic engineering and surveying. He was thought to have invented the decimal fractions until the middle of the 20th century, when researchers discovered that decimal fractions had been previously introduced by the medieval Islamic scholar al-Uqlidisi in a book written in 952. Moreover, a systematic development of decimal fractions was given well before Stevin in the book Miftah al-Hisab written in 1427 by Al-Kashi. His contemporaries were most struck by his invention of a so-called land yacht, a carriage with sails, of which a model was preserved in Scheveningen until 1802. The carriage itself had been lost long before. Around the year 1600 Stevin, with Prince Maurice of Orange and twenty-six others, used the carriage on the beach between Scheveningen and Petten. The carriage was propelled solely by the force of wind and acquired a speed which exceeded that of horses. Management of waterways Stevin's work in the waterstaet involved improvements to the sluices and spillways to control flooding, exercises in hydraulic engineering. Windmills were already in use to pump the water out but in Van de Molens (On mills), he suggested improvements including ideas that the wheels should move slowly with a better system for meshing of the gear teeth. These improved threefold the efficiency of the windmills used in pumping water out of the polders. He received a patent on his innovation in 1586. Philosophy of science Stevin's aim was to bring about a second age of wisdom, in which mankind would have recovered all of its earlier knowledge. He deduced that the language spoken in this age would have to be Dutch, because, as he showed empirically, in that language, more concepts could be indicated with monosyllabic words than in any of the (European) languages he had compared it with. This was one of the reasons why he wrote all of his works in Dutch and left the translation of them for others to do. The other reason was that he wanted his works to be practically useful to people who had not mastered the common scientific language of the time, Latin. Thanks to Simon Stevin the Dutch language got its proper scientific vocabulary such as "wiskunde" ("kunst van het gewisse of zekere" the art of what is known