Manchester Memoirs, Vol. lix. (191 5), No. 11. 



his discoveries was the so-called hydrostatic paradox. 2 

 He further also determined the measure of the pressure 

 of a liquid on any given portion of the side of a vessel. 

 These discoveries are important complements to Archi- 

 medes' hydrostatics. He also demonstrated the resolution 

 of forces, which is a consequence of the law of their 

 composition. All these principles are still expounded in 

 the most modern physics text-books. 



In 1586 Stevin published in Dutch a pamphlet by 

 which he established the daily use of decimal fractions. 

 He also declared the introduction of a decimal coinage, 

 measures and weights to be only a matter of time. 3 



One of his most curious inventions was that of the 

 zeilwagen (literally, sail-wagon). It was a carriage fitted 

 with sails and propelled by the wind, and was able to 

 attain a speed greater than that of a galloping horse. The 

 zeilwagen appealed vividly to the popular imagination, 

 and the memory of it has been preserved by tradition 

 even to our own times. 



Simon Stevin learned book-keeping by double entry, 

 probably through studying Italian writers during his stay 

 at Antwerp, where he was for some time commercially 

 employed at the beginning of his career. He realised 

 the advantage of this method, and he had the honour of 

 being the first to recommend its application to public 

 accounts. He practised its use himself in the service of 

 Prince Maurice of Nassau, and recommended it to Sully, 

 a French statesman. 



It was during the period in which Simon Stevin lived 

 that Philip II., King of Spain, endeavoured to destroy 



- The downward pressure of a liquid contained in a vessel is indepen- 

 dent of the quantity of liquid and theshapc of the vessel, and depends only 

 on its height and base. 



3 In this pamphlet he does not even avoid fractional exponents. 



