Our Sea

Part 4 - Art, Science and Engineering

Thucydides (460 - 400 BCE) is regarded as the father of "scientific history" after his History of the Peloponnesian War which described the 5th century BCE war between Sparta and Athens up to the year 411 BCE. He also explained human behaviour in crises such as plagues, massacres, and civil war, and proposed that relations between people and states were controlled by fear and self-interest. His Melian dialogue is still considered a significant work of international relations theory.

Hippocrates of Kos (460 - 370 BCE), is considered the, "Father of Medicine." As the founder of the Hippocratic School of Medicine he revolutionized medicine in ancient Greece and established medicine as a profession. He is best know for the Hippocratic Oath, (First, do no harm) which is still in use today. Hippocrates is credited with advancing the systematic study of medicine, summing up the medical knowledge and prescribing practices for physicians in works like the Hippocratic Corpus.

Aristotle (384 - 322 BCE) was a philosopher and scientist who, along with Plato, is regarded as one of the "Father of Western Philosophy." Aristotle synthesized much of the existing work of previous philosophers, including Socrates and Plato, and transmitted the ideas that form the fundamental basis of Western civilization. 

Archimedes of Syracuse (287 - 212 BCE) was a mathematician, engineer, inventor and astronomer who anticipated modern calculus by applying concepts of infinitesimals and the method of exhaustion to prove a range of geometrical theorems, including the area of a circle, the surface area and volume of a sphere, and the area under a parabola. He derived an accurate approximation of Pi, defined the Archimedean spiral and created exponentials to express very large numbers. He was also one of the first to apply mathematics to physical phenomena and is credited with machines, such as his screw pump, compound pulleys, and defensive war machines. His most famous discovery was a method of obtaining the volume of an irregularly shaped object. He demonstrated that a supposedly pure gold crown had been made with some silver added, by measuring the volume of water it displaced, thus proving that it was less dense than pure gold.

Archimedes died during the Roman siege of Syracuse despite orders that he should not be harmed. Cicero describes visiting the tomb of Archimedes, which was surmounted by a sphere and a cylinder, which Archimedes had requested be placed on his tomb to represent his mathematical discoveries.

Eratosthenes (275 - 195 BCE) coined the term, "geography", and was the first person to determine the Earth's circumference to within 0.5 percent accuracy after learning of a well in the Egyptian city of Swenett (modern Aswan) into which the sun shone directly only on the summer solstice. On that day, he comparing the length of shadows in Alexandria, 524 miles (843 km) farther North. This provided the angular difference between the two points which he divided into 360 degrees. He went on to create charts with meridians (north-south lines) and parallels(west-east lines) with their origin in the city of Rhodes. These axis lines were placed over the map of the earth and divided the world into sectors.

Claudius Ptolemy (90 - 68 CE) revolutionized map making by using perspective projection to depict the spherical earth on a map and suggesting precise methods for fixing the position of geographic features on its surface using astronomy and mathematics with a coordinate system of parallels of latitude and meridians of longitude. 

Aelius Galenus or Claudius Galenus (or Galen) (129 - 200 or 216 CE) was a Greek physician, surgeon and philosopher in the Roman Empire and an accomplished medical researcher on anatomy, physiology, pathology, pharmacology, and neurology.

Galen's theories of anatomy and medicine, based on Hippocrates ideas, and his anatomical studies, based mainly on dissection of monkeys and pigs, remained uncontested until 1543, when descriptions and illustrations of human dissections were published in the work De Humani Cabrica by Andreas Vesalius.

Galen's theory of the circulatory system remained unchallenged until about 1242 CE, when Ibn al-Nafis published his book Commentary on Anatomy in which he reported his discovery of the pulmonary circulation (of blood).

Because of the collapse of the Roman Empire, medieval Europe suffered intellectual stagnationuntil Mondino de Luzzi (1275 - 1326) produced the first known anatomy textbook based on human dissection.

Hero (or Heron) of Alexandria (10 - 70 CE) Heron of Alexandria, one of the greatest engineers of antiquity, used mathematics and empirical experiments instead of the deductive approach used by previous mathematicians.

His most famous invention, the Aeolipile, a hollow sphere rotated by jets of steam, was the world's first steam turbine and it was almost 1800 years before Newcomen's steam engine.

Heron described a force pump used to deliver air or liquids. This was a piston in a cylinder device widely used as a fire engine pump in Roman times and is still used in many air compressors and water pumps as well as most land vehicle engines.

The Dioptra, the ancestor of the modern theodolite and sextant, probably existed before Heron's time, but he wrote extensively of its use for surveying and astronomy by Roman surveyors. It consisted of a disc marked with angles and supported on a base. The surveyor used small water levels for accuracy before rotating the disc to measured the angle between two distant objects and, using trigonometry, calculate the distance between the two objects. The disc could also be tilted to measure vertical angles as a way to calculate the height of distant buildings or hills or the position of stars.

Heron designed a door opener for the local temple so that when the priest lit a fire on the altar it heated the air in a closed container. The increased air pressure forced water into a bucket which moved down and opened the door via a rope. When the fire was removed, the air cooled and the partial vacuum sucked the water back into the container. The bucket returned to its original position and the door was closed by a counterweight.

He also constructed the first vending machine. When a coin was dropped into a slot, it fell onto a pan attached to a lever which opened a valve letting out a measured amount of holy water. The lever continued to tilt until the coin fell off allowing a counterweight to return the lever to its original position and close the valve.

Heron's fountain seemed to power itself. Water, poured into a funnel, compressed the air in a sealed reservoir and the compressed air was directed into the second reservoir, where it forced water out in a powerful jet. This continued until the first reservoir was filled with water, when it had to be drained.

Heron discovered that, if a ray of light travelled from point A to point B within the same medium, it followed the shortest possible distance. It was nearly 1000 years later that Alhacen expanded the principle to both reflection and refraction.