PAPIN 119 



Magdeburg experiments, put the great powers of the atmos- 

 pheric pressure into the minds of all investigators, and Huy- 

 gens at that time designed a machine which was to pump 

 the water out of the Seine for Louis XIV's fountains by 

 means of atmospheric pressure. Papin carried out the 

 machine and introduced it in the year 1674 to the minister 

 Colbert. It consisted of a cylinder with a piston; this was 

 first pushed upwards by gunpowder ignited on the floor of 

 the cylinder, the excess of the gaseous products of com- 

 bustion escaping by valves at the upper end of the cylinder; 

 then, when the gases had cooled off^, the air pressure drove 

 the cylinder down, whereby it actuated the water pump 

 through a rope running over a pulley. For every stroke, 

 fresh power had to be introduced into a small hold under- 

 neath the cylinder, and set on fire.^ 



Boyle in England had his attention drawn to Papin, no 

 doubt by Leibniz, and invited him thither in the year 1675; 

 he was to help him in his air-pump experiments and other- 

 wise. Papin fulfilled this task in such a way, that in five 

 years he was made a member of the Royal Society on Boyle's 

 proposal. On this occasion he presented a paper on the 

 'Digester' which he had just invented, and which is still 

 known under his name to-day, being used for cooking under 

 increased pressure. In this Papin also introduced the safety- 

 valve, which enables high pressures to be limited, and is to 

 be found on every steam boiler. He also observed the de- 

 pendence of the boiling point upon the pressure, although at 

 that time the temperatures were estimated only by the time 

 of evaporation of a certain quantity of water from a hollow 

 in the lid of the pot. Soon afterwards, Papin accepted an 

 invitation to Venice to found a scientific academy, but only 

 remained there two years, returning to the Royal Society 



^ We see that this motor was the forerunner of the later gas-engines 

 which were introduced in about 1873, which also operated by air pres- 

 sure, and made use of a mixture of illuminating gas and air instead of 

 gunpowder. 



