Despite the fact that the modern world is at one of the peaks of technological development, not all knowledge of the past has survived to this day. Actually, it seems that some inventions were lost, and some old technologies are incomprehensible to contemporaries. Below are five lost technologies that still attract the attention of scientists.
Roman cement
Modern concrete, which is a mixture of cement, water and aggregates such as sand or gravel, was invented in the early 18th century and is the most common building material in the world today. However, the composition developed in the 18th century is far from the first type of concrete. Basically, the Persians, Egyptians, Assyrians and Romans used concrete. The latter added quicklime, crushed stone and water to the building mixture - it was this composition that gave Rome the Pantheon, the Colosseum, aqueducts and thermal baths.
Like many other knowledge of antiquity, this technology was lost with the onset of the Middle Ages - it is not strange that this historical era is also known as the Dark Ages. According to the popular version explaining the disappearance of the recipe, it was something of a commercial secret and with the death of the few people who were privy to it, it was forgotten.
It is noteworthy that the components that distinguish Roman cement from modern cement still remain unknown. Buildings erected with the use of Roman cement have stood for millennia, despite the effects of the elements - the cement used in our time cannot boast of such resistance. Some historians believe that the Romans added milk and blood to the building mix - it is assumed that the pores formed through this process allowed the composition to expand and contract under the influence of temperature changes, without collapsing. However, the strength of the cement was crushed by other substances, but no one can say for sure which ones.
Damascus steel
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Damascus steel, an incredibly strong type of metal, was widely used in the Middle East around AD 1100-1700. Basically, this type of steel became known thanks to the swords and knives that were made from it. Blades forged from Damascus steel were famous for their strength and sharpness: it was believed that a Damascus sword could easily cut stones and other metals, including armor and weapons made from weaker alloys.
Damascus steel is associated with patterned crucible steel from India and Sri Lanka. The high strength of blades made of such steel was due to the manufacturing process, during which hard cementite was mixed with slightly softer iron, as a result of which the products were both strong and flexible.
The technology of forging Damascus steel was lost around 1750. The exact reasons why this happened are unknown, but there are several versions that explain these reasons in one way or another. The most popular theory is that the ore needed to make Damascus steel was running low and gunsmiths were forced to switch to alternative blade technologies.
According to another version, the blacksmiths themselves did not know the technology - they simply forged many blades and tested them for strength. It is assumed that, by coincidence, some of them acquired properties characteristic of Damascus. Be that as it may, even at the current stage of technology development, it is impossible to accurately reconstruct the process of creating Damascus steel. Despite the fact that blades with a similar pattern still exist today, modern craftsmen are still unable to achieve the strength of Damascus steel.
Antikythera mechanism
One of the most mysterious archaeological finds, the Antikythera Mechanism, was found by divers on a sunken ancient ship near the Greek island of Antikythera in the early 20th century. After studying the traces of a shipwreck, scientists came to the conclusion that the ship dates from the 1st or 2nd century BC. At the same time, the found mechanism was incredibly complex in its structure: it consisted of more than 30 gears, levers and other components.
Moreover, it used a differential transmission, which, as previously assumed, was not invented until the 16th century. Obviously, the device was intended to measure the position of the Sun, Moon and other celestial bodies. Describing this mechanism, some experts call it the original form of mechanical watches, while others consider it the first known analog computing machine.
The precision with which the components of the movement were made indicates that the device was not unique. On the other hand, historical records of mechanisms, the structure of which resembles a find, date back to the 14th century, which means that the technology has been lost for more than 1400 years.
Greek fire
Greek fire, a combustible mixture used for military purposes by the Byzantine Empire and other states, is one of the most famous lost technologies. Something like the original form of napalm, Greek fire continued to burn even in water. The most famous use of this formidable weapon took place in the 11th century, when Byzantium used fire against the Arabs and put them to flight.
At first, Greek fire was poured into small vessels, which were set on fire and thrown at the enemy, like the modern Molotov cocktail. Later, installations consisting of copper pipes with a siphon were invented - these combat vehicles were used to set fire to enemy ships. In addition, there is information about manual installations that vaguely resembled modern flamethrowers.
Of course, the armed forces of our time use combustible mixtures, which means that the technology cannot be said to be completely unknown. On the other hand, napalm was not developed until the 40s of the twentieth century, and the original composition of Greek fire was lost after the decline of the Byzantine Empire - thus, an effective technology, however, remained lost for several centuries. It is still difficult to say exactly how the composition of the substance was lost. Plus, scientists don't know what could have been used to make the mixture.
According to the earliest version, the Greek fire may have included a large dose of saltpeter. However, this version was soon rejected, because saltpeter does not burn in water, and it was this property that was attributed to Greek fire. If you believe a newer theory, the combustible substance was a kind of cocktail of petroleum products or crude oil, as well as quicklime, potassium nitrate, and possibly sulfur.
Apollo and Gemini technologies
It turns out that not all lost technologies originated in antiquity - even relatively recent advances in science and technology may remain incomprehensible to contemporaries. In the 50s, 60s and 70s of the twentieth century, the space programs Gemini and Apollo led to the most notable achievements of mankind in the field of space flight. In particular, we are talking about the biggest success of NASA, namely, the Apollo 11 program and the landing of a man on the moon. In turn, the earlier Gemini program of 1965-66. gave scientists valuable knowledge about the mechanics of space flight.
Of course, the achievement of the Gemini and Apollo programs cannot be considered lost in the traditional sense of the word, because the scientists still have the Saturn-5 launch vehicles at their disposal, as well as fragments of other spacecraft. On the other hand, possession of mechanisms does not yet imply knowledge of technology. The fact is that as a result of the high pace of the "space race", documentation was not conducted as well as modern NASA workers would like. In addition to the rush, the situation is exacerbated by the fact that private contractors were hired to prepare the programs to work on individual components of the ships and equipment.
After the programs were completed, the private engineers left, taking their blueprints and diagrams with them. As a result, now that NASA is planning a new flight to the moon, large amounts of necessary information remain unavailable or are in a completely chaotic state. Basically, all that remains for NASA in the current circumstances is to turn to reverse engineering, that is, to the analysis of the available ships.