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Otto GuerickeIn science, Otto von Guericke (1602-1686) was a German engineer and physicist notable for the inventions of the vacuum pump (1647), piston and cylinder, and the Magdeburg hemispheres (1654). With these instruments, Guericke showed that it was possible, manually, to create a vacuum or to remove the air from a sealed volume.

This, essentially, disproved the age-old postulate, argued in c. 485 BC by Greek philosopher Parmenides, that nature abhors a vacuum (horror vacui) or that a void could not exist. Guericke also showed that a vacuum, such as found in an evacuated piston and cylinder, in connection to a pulley system, possessed the property that it could be made to raise a weight vertically, in other words it could do work. In the early 1650s, Guericke began demonstrating these principles in large public venues throughout Europe.

Thermodynamics
Guericke's inventions were the technological seeds that led to the development of the science of thermodynamics. In short, Guericke's vacuum pump (1650) led to the first steam engine design, by French physicist Denis Papin (1690), which led to the construction of the first steam engine, by English engineer Thomas Savery (1697), which led to latter improved steam engine designs, such as the steam engines built by English engineer Thomas Newcomen (1710) and Scottish engineer James Watt (1763-75), and to the first treatise on the physics of steam engine or heat engines, by French engineer Sadi Carnot titled Reflections on the Motive Power of Fire (1823).

Vacuum pumpVacuum pump
In 1647, Guericke began to invent suction pumps and in 1850, after several prototypes, invented a working vacuum pump, shown adjacent, that was used to remove air from an attached spherical vessel. The pump had a copper bowl fasted to the upper end of the barrel and a pail of tin-plate attached to its lower end, which were filled with water or oil to prevent leakage of air at the joints. The machine had no valves; merely a plug in the top of the barrel and a stop-cock on the receiver. [2]

Piston and cylinder demonstrations
To visually show the effect of a vacuum, Guericke designed a piston and cylinder, pictured below, and conducted various demonstrations to demonstrate its power of the weight of the atmosphere. The air cylinder a was about twenty-inches high and fifteen-inches wide, having its sides perfectly even and parallel, which could be fixed firmly in a vertical position by the ring s. The piston, p, q, r, was made to fit exactly inside of the cylinder, p being of iron and q wood, and the rounded head r, formed of hard oak, had a grove on its edge which was filled with flax or hemp. Piston and cylinder

To demonstrate the power or strength of the vacuum, the piston was let into the cylinder, and its iron handle was passed through the ring of the arm o, shown below, in such a manner that it could move freely up and down through the whole height of the cylinder and at the same time be preserved in a straight line. In a first experiment, the piston was positioned at the bottom of the cylinder the stop-cock x was closed. In this arrangement, the joint efforts of twenty or more men could not raise the piston more than halfway up. The men, in effect, were not just pulling on the piston, but the weight of a column of atmosphere 62-miles high.

In a second experiment, with the men pulling on the piston at the halfway up position, a large glass receiver, which had been mad perfectly vacuous by Guericke’s pump, was then applied to the stop-cock; and when the men were exerting their utmost force, on a communication being opened between the receiver and the cylinder, the piston was suddenly forced down to the bottom of the cylinder in spite of the efforts of the men to keep it up.

Guericke's weight rasing machines
In a third demonstration of 1654, Guericke arranged the piston at the top of the cylinder, having a scale loaded with 2,686 lbs attached to it, shown above right. In this configuration, a little boy, by means of a small syringe applied at the stop-cock x to pump out the air, was able to bring down the piston and raise the weight. [2]

Magdeburg hemispheres (illustration + monument)Magdeburg hemispheres
In his most famous experiments, performed between 1654 and 1663, Guericke removed the air from to copper hemispheres fit together, sealed with grease at their rims, in such a manner to form hollow copper spherical vacuum. He then showed that two teams of horses, ranging from 8-15 per team, harnessed to each sphere, respectively, in opposite directions, could not pull the hemispheres apart. Guericke's demonstration was first performed on 8 May 1654 in front of the Reichstag and the Emperor Ferdinand III in Regensburg, in which thirty horses, in two teams of 15, could not separate the hemispheres until the vacuum was released. [3]

Steam engine
The logic of these instruments, experiments, and public demonstrations functioned to stimulate the later development of the steam engine. Specifically, Guericke’s vacuum pump was first described in the book 1657 book Mechanical Hydraulic Pneumatics by German scientist Gaspar Schott, a correspondent of Guericke, Dutch mathematical physicist Christiaan Huygens, and English physicist and chemist Robert Boyle who read the book. [4] Boyle and his assistant Robert Hooke then improved Guericke's air vacuum design and built their own in 1658, one that also functioned as a pump. [1]

Several decades later, in the 1690 memoir "A New Method to Obtain Very Great Motive Powers at Small Cost", Boyle and Huygen's associate French engineer Denis Papin conceived that the quick condensation of steam in a cylinder, via contact with a cold body, would quickly make a vacuum that would drive the piston down in such a manner that if the process was repeated in a cyclical manner useful work, as in raising weights out of mines, could be obtain. This design was later used by English engineers Thomas Savery, in 1697, and Thomas Newcomen, in 1710, to make the first working steam engine.

References
1. Wilson, George. (1849). “On the Early History of the Air-Pump in England”, The Edinburgh New Philosophical Journal, (pgs. 330-54).
2. Galloway, Robert L. (1881). The Steam Engine and its Inventors. London: MacMillan and Co.
3. Von Guericke, Otto. Encyclopaedia Britannica, 11th Edition 9. (1910). The Encyclopaedia Britannica. 670.
4. Schott, Gaspar. (1657). Mechanical Hydraulic Pneumatics (Mechanicahydraulica-pneumatica). Würtzburg.

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