HERO

Hero

The first experiments with steam have been made by Hero of Alexandria 120 A.C. He built many mechanical devices, which seldomly performed any useful work. Hero among other things invented a steamball (see the animation on the left side) and a templedoor-opener (see picture on the right side). The templedoor-opener was not that economical. The steam condensed all the time on the surface of the cold water, but no handworker was able to produce a piston at that time. Although the engine was already very sophisticated, his knowledge was shifted to the background for many years and, only in the 17th century, concrete success was made.

Enlarge (84 K). Heros steamball On the right side, the fire is heating the water so that its vapors could go through a pipe in the hollow ball. Because this ball is revolving on a pivot, steam - which passes out through the bent tubes - makes the ball turn.

Enlarge (19 K). Heros Templedoor-opener If the priest makes a fire over the altar the air inside it is heated too and presses the water out of the sphere and into the bucket. The bucket itself is connected with a cord, which is connected on a revolving column, and turns it while moving downward. Therefore, the doors of the temple open. At the end of the ceremony, the priest puts the fire out, the air cools down, the pressure is going down, the water flows back into the sphere and the doors close because there is a weight that turns the columns back.

Enlarge (23 K). Salomon de Caus apparatus (1611)

Giambattista della Porta and Salomon de Caus

In 1609, the Italian Giambattista della Porta succeeded in showing that water can be raised with fire. He filled a retort (a vessel that has a wide bottom that leads into a thin pipe) with water and put it over a fire. He then put the pipe into a air-tight vessel filled with water. When the water in the retort began to vaporize an excess pressure took place in the vessel above it. Porta put another pipe into it, so that the water could be pressed out of the vessel.
Salomon de Caus built in 1611 a very similar apparatus. He fusioned all the pieces from Portas apparatus in one copper vessel. Heating the vessel, which has been filled with water before, pressed all water out of it. 
 

 

 

 

Hero (Heron) of Alexandria (AD 20-62)
A Greek mathematician, scientist and inventor who is mostly renowned for his works in mechanics, mathematics and physics. Although there were about 18 Greek writers under the name of Hero or Heron, this specific Greek scientist was known as Hero or Heron of Alexandria.

Heron is believed to have been born in Egypt in the year 20.

Most of his works were accomplished in Alexandria, Egypt. He developed many mechanical machines that had practical uses. They included a water organ, fire engine, a coin-operated device, and the aeolipile. The latter device was the earliest known steam-powered engine, which was a rotary steam engine that consisted of a sphere mounted on a boiler and having two canted nozzles to produce a rotary motion from the escaping steam. The siphon, known as Hero's fountain, was an instrument that produces a vertical jet of water by air pressure. The dioptra was a primitive surveying device.

Heron was well known for his studies in geometry (a branch of mathematics that studies the relationships, measurements and properties of points, lines, angles and solids) and in geodesy (a branch of mathematics that searches to determine the size and shape of earth, and the location of objects or areas on the earth).
One of his most important works was the collection of his books of Metrica, which was found in the year 1896. In Book I he portrays a derivation of Heron's formula that expresses the are of a triangle in terms of its sides. This formula originated from his attempt to demonstrate that the angle of incidence in optics is equal to the angle of reflection. Book II of the Metrica describes methods of calculating or finding the volumes of bodies such as cylinders, cones, pyramids, prisms, parallelepipeds, spheres, etc. Book III covers the division of volumes and areas into parts of given ratios. He also wrote books based on mechanics and other subjects. Among those are Automatopoietica, Pneumatica, Belopoeica, and Cheirobalistra.

Hero of Alexandria died in the year 62.