Simon Stevin, a Flemish mathematician who had been a merchant's clerk in Antwerp for a time, has eventually risen to become commissioner of public works and quartermaster general of the army under Maurice.

He engineers a system of sluices to flood certain areas and drive off any enemy, an important defense of Holland.

He also invents a twenty-six-passenger carriage with sails for use along the seashore.

Stevin had in 1585 published a small pamphlet, La Thiende (“The Tenth”), in which he presented an elementary and thorough account of decimal fractions and their daily use.

Although he is not the inventor of decimal fractions and his notation is rather unwieldy, he has established their use in day-to-day mathematics.

He declares that the universal introduction of decimal coinage, measures, and weights will be only a question of time.

The same year he had written La Disme (“The Decimal”) on the same subject.

In De Beghinselen der Weeghconst (1586; “Statics and Hydrostatics”) Stevin publishes the theorem of the triangle of forces.

The knowledge of this triangle of forces, equivalent to the parallelogram diagram of forces, gives a new impetus to the study of statics, which had previously been founded on the theory of the lever.

He also has discovered that the downward pressure of a liquid is independent of the shape of its vessel and depends only on its height and base.

In a refutation of Aristotle's doctrine that heavy bodies fall faster than light ones, Stevin publishes a report in 1586 on his experiment in which two lead spheres, one ten times as heavy as the other, had fallen a distance of thirty feet in the same time.

His report receives little attention, though it precedes by three years Galileo's first treatise concerning gravity and by eighteen years Galileo's theoretical work on falling bodies.