Despite these setbacks, European scientific institutions overcame the challenges by the church, taking over the flame carried by the Arabs and the sixteenth and seventeenth centuries became the age of Scientific Revolution in Europe. Like Thalesdelta 10 professional radial arm saw 33 830 had travelled to Egypt and Babylon where he studied astronomy and geometry. Admiral Zheng Hea muslim eunuch, castrated as a boy when the Chinese conquered his tribe, had recently completed an audacious voyage of exploration on behalf of a previous Ming emperor Yongle to assert China's control of all of the known world and to extract tributary from its intended subjects. Charged with heresy, Galileo was made to kneel before the inquisitor and confess that the heliocentric theory was false. Inthe line of handheld power tools was sold to Pentair Inc.

First he drew a regular hexagon inside a circle and computed the length of its perimeter. Then he improved the accuracy by progressively increasing the number of sides of the polygon and calculating the perimeter of the new polygon with each step.

As the number of sides increases, it becomes a more accurate approximation of a circle. At the same time, by circumscribing the circle with a series of polygons outside of the circle, he was able to determine an upper limit for the perimeter of the circle. As with many great men of antiquity, few if any, contemporary records of Archimedes works remain and his reputation has been embellished by historians writing about him many years after his death, or trashed by artists, ignorant of the scientific principles involved, attempting to illustrate his ideas.

This is probably the case with four of the oft quoted anecdotes about his work. Over the years, in the absence of written records, other artists and illustrators have tried to depict Archimedes devices and mechanisms. Examples of how the artists have imagined these devices are shown in the page about Archimedes' Machines. While taking a bath, he noticed that the level of the water in the tub rose as he got in, and realised that this effect could be used to determine the volume of the crown. By immersing the crown in water, the volume of water displaced would equal the volume of the crown.

If any of the gold had been replaced by silver or any other less dense metal, then the crown would displace more water than a similar weight of pure gold. It was reported that Archimedes then took to the streets naked, so excited by his discovery that he had forgotten to dress, crying "Eureka! The test was conducted successfully, proving that silver had indeed been mixed in.

There is no record of what happened to the goldsmith. It is claimed today that the change in volume would probably have been so small as to be undetectable by the apparatus available to Archimedes at the time. There is no question however that he devised a method of measuring the volume of irregularly shaped objects and also understood the principle of buoyancy and its use for comparing the density of the materials used in different objects, but the story of him running naked through the streets is probably apocryphal.

All of these stories probably contain a major element of truth and it would not be surprising that Archimedes was well aware of, and had publicised, the theoretical possibilities involved in these schemes, but whether they could have actually been successfully implemented with the available technology and materials of the day is open to question. The principles were correct but the scale and effectiveness of the devices described in biographies written hundreds of years later was doubtful.

There is unfortunately no corroborating evidence to back up these later descriptions of the military exploits. If the naval siege defences had been so successful, why would they not have been subsequently adopted as standard practice and why did they not appear in historical accounts of the battles?

Archimedes skills in designing military machines and mechanical devices were well known, even to the Romans, and were called upon in the defence of Syracuse during these hostilities.

Greek historian Plutarch C. The first describes how Archimedes was contemplating a mathematical problem on a diagram he had drawn in the dust on the ground when he was approached by a Roman soldier who commanded him to come and meet General Marcellus who considered the great inventor to be a valuable scientific asset who should not be harmed. But Archimedes declined, saying that he had to finish working on the problem.

The soldier was enraged by this, and ran him through with his sword, much to the annoyance of Marcellus. The second account explains that Archimedes was killed by a soldier while attempting to rob him of his valuable mathematical instruments. Recent examination of all the accounts by both Carthaginian and Roman historians of the details of Archimedes' death have however reached a different conclusion.

As we know, history is often written by the winners. The counter view is that Archimedes' death was the state-sponsored assassination of an enemy of Rome, a key player, whose inventions were vital to the defence of Syracuse. The nations were at war. Why would Archimedes be so oblivious to the danger he was in?

Marcellus' feigned sorrow and anger after the event were a cover for his guilt at ordering the death of the World's greatest scientist at the time. The Baghdad Battery - In several unusual earthenware jars, dating from about B. An iron rod was suspended from an asphalt stopper at the top of the copper cylinder into the centre of the cylinder. The rod showed evidence of having been corroded with an acidic agent such as wine or vinegar.

Baghdad was not founded until A. A mysterious anachronism. Since then, several replica batteries have been made using various electrolytes including copper sulphate and grape juice generating voltages from half a Volt to over one Volt and they have successfully been used to demonstrate the electroplating of silver with gold.

One further, more recent, suggestion by Paul T. Keyser a specialist in Neat Eastern Studies from the University of Alberta is that the galvanic cells were used for analgesia. There is evidence that electric eels had been used to numb an area of pain, but quite how that worked with such a low voltage battery is not explained.

Apart from that, no other compelling explanation of the purpose of these artifacts has been proposed and the enigma still remains. Despite warnings about the safety of these priceless articles before the invasion of Iraq, they were plundered from the museum during the war and their whereabouts is now unknown. The Parthians were nomadic a nomadic tribe of skilled warriors and not noted for their scientific achievements. The importance of such an unusual electrical phenomenon seems to have gone completely unrecorded within the Parthian and contemporary cultures and then to have been completely forgotten despite extensive historical records from the period.

There are also some features about the artifacts themselves which do not support the battery theory. The asphalt completely covers the copper cylinder, electrically insulating it so that no current could be drawn without modifying the design and no wires, conductors, or any other sort of electrical equipment associated with the artifacts have been found.

Furthermore the asphalt seal forms a perfect seal for preventing leakage of the electrolyte but it would be extremely inconvenient for a primary galvanic cell which would require frequent replacement of the electrolyte. As an alternative explanation for these objects, it has been noted that they resemble storage vessels for sacred scrolls.

It would not be at all surprising if any papyrus or parchment inside had completely rotted away, perhaps leaving a trace of slightly acidic organic residue. Greek mathematician Eratosthenes B. Considering the tools and knowledge available at the time, Eratosthenes results are truly brilliant.

Equipped with only a stick, he did not even need to leave Alexandria to make this remarkable breakthrough. Not only did he know that the Earth was spherical, years before Columbus was born, he also knew how big it was to an accuracy within 1. See Eratosthenes Method and Calculation. He invented the discipline of geography including the terminology still used today and created the first map of the world incorporating parallels and meridians , latitudes and longitudes based on the available geographical knowledge of the era.

Eratosthenes also devised a way of finding prime numbers known as the sieve. Instead of using trial division to sequentially test each candidate number for divisibility by each prime which is a very slow process, his system marks as composite i. The multiples of a given prime are generated as a sequence of numbers starting from that prime, with constant difference between them which is equal to that prime.

The magnetic compass was invented by the Chinese during the Qin Chin Dynasty, named after China's first emperor Qin Shi Huang di , the man who built the wall. It was used by imperial magicians mostly for geomancy Feng Shui and fortune telling but the "Mighty Qin's" military commanders were supposed to be the first to use a lodestone as a compass for navigation. Chinese compasses point south. During the Han Dynasty, Chinese historian Ban Gu recorded in his Book of Han the existence of pools of "combustible water", most likely petroleum , in what is now China's Shaanxi province.

During the same period, in Szechuan province, natural gas was also recovered from what they called "fire wells" by deep drilling up to several hundred feet using percussion drills with cast iron bits. These fuels were used for domestic heating and for extracting metals from their ores pyrometallurgy , for breaking up rocks as well as for military incendiary weapons.

The heavy oil was also distilled to produce paraffin kerosene for use in decorative oil lamps from the period which have been discovered. Percussion drilling involves punching a hole into the ground by repeatedly raising and dropping a heavy chisel shaped tool bit into the bore hole to shatter the rock into small pieces which can be removed.

The drill bit is raised by a cable and pulley system suspended from the top of a wooden tower called a derrick. It was over years before the first oil well was drilled by Edwin Drake in the USA and he used the same percussion drilling method as the Chinese. Paper was first produced in China in the second century B. Made by pounding and disintegrated hemp fibres, rags and other plant fibres in water followed by drying on a flat mould, the paper was thick and coarse and surprisingly it was not used for writing but for clothing, wrapping, padding and personal hygiene.

The oldest surviving piece of paper was found in a tomb near Xian and dates from between B. The first paper found with writing on it was discovered in the ruins of an ancient watch tower and dates from A. The development of this finer paper suitable for writing is attributed to Cai Lun , a eunuch in the Imperial court during the Han dynasty B. Paper was an inexpensive new medium which provided a simple means of communicating accurately with others who were not present without the danger of "Chinese whispers" corrupting the message, but more importantly, it enabled knowledge to be spread to a wider population or recorded for use by future generations.

A simple invention which, like the printing press, brought enormous benefits to society. See more about Chinese Inventions. The Roman Empire. The Romans were great plumbers but poor electricians. The Romans were deservedly renowned for their civil engineering - buildings, roads, bridges, aqueducts, central heating and baths.

Surprisingly however, in years, they didn't advance significantly on the legacies of mathematics and scientific theories left to them by the Greeks. Fortunately, the works of the Greek philosophers and mathematicians were preserved by Arab scholars who translated them into Arabic. Circa 15 B. Some time between 27 B. C and 15 B. It is a comprehensive manual for architects covering the principles of architecture, education and training, town planning, environment, structures, building materials and construction methods, design requirements for buildings intended for different purposes, proportions, decorative styles, plans for houses, heating, acoustics, pigments, hydraulics, astronomy and a ranges of machinery and instruments.

His philosophies about architecture are summed up in the Vitruvian Virtues that a structure must exhibit the three qualities of firmitas, utilitas, venustas - meaning that it must be solid, useful and beautiful. Included in Book 10 of the study are designs for military and hydraulic machines, including pulleys and hoists and designs for trebuchets , water wheels and armoured vehicles which have had an undeniable influence on the inventions of Leonardo da Vinci.

See more about Vitruvius water wheels. Amongst Vitruvius' designs are instructions for the design of an odometer which he called a "hodometer". It consisted of a cart with a separate, large wheel of known circumference mounted in a frame. The large wheel was connected through the intermediate gear wheel of a reduction gear mechanism to a horizontal disk with a series of holes around its rim each containing a small pebble.

A single hole in the housing of the horizontal disk allowed a pebble to fall through into a container below when it arrived above the hole. As the cart was pushed along the ground, one pebble would fall into the container for each revolution of the intermediate gear wheel. The distance traveled could be calculated by counting the number of pebbles in the container and multiplying by the circumference of the large wheel and the gear ratio.

Vitruvius also proposed a marine version of his device in which the distance was calculated from the rotation of paddles. There are some who attribute the design of the odometer to Archimedes , but there is no strong evidence to support this.

Unfortunately none of the original illustrations from "De Architectura" have survived. Nevertheless the books have deeply influenced classical architects from the Renaissance through to the twentieth century. He was perhaps a little too influential though, through no fault of his own, since his style was so sublime that it captured public taste, stifling further innovation and generations of architects merely copied his ideas rather than developing alternative styles of their own.

Circa 50 A. In the first century A. See pictures of these two Roman Aqueducts. In the absence of records the design and construction of the Pont du Gard has been attributed to Marcus Agrippa , the adopted son-in-law of Emperor Augustus at around the year 19 B.

However recent excavations and coins depicting the Emperor Claudius A. The aqueduct supplied Nimes with water and is nearly 30 miles 50 kilometres long. The section over the river Gard has arches at three levels and is feet metres long and feet 49 metres high.

The top level contains a channel 6 feet 1. The bottom level carries a roadway. The three levels were built in dressed stone without mortar.

Some researchers have estimated that the Delta Radial Arm Saw Rs 830 Zip Segovia aqueduct was started in the second half of the 1st Century A. Others have suggested it was started under Emperor Domitian A. The aqueduct brought water to Segovia from the Frio River 10 miles 16 km away. Its maximum height is 93 ft 6 in The bridge section of the aqueduct is feet meters long and changes direction several times. Like the Pont du Gard, it was built from dressed stone without mortar. Circa 60 A. Greek mathematician Hero of Alexandria conceived the idea of a reaction turbine though he didn't call it that.

It was a hollow sphere containing a small amount of water, free to rotate between two pivot points. When heated over a flame the steam from the boiling water escaped through two tangential nozzles in jets which caused the sphere to rotate at high speed. See diagram of Hero's Aeolipile. Alternative designs show the water boiled in a separate chamber being fed through a hollow pipe into the sphere through one of the pivots.

It has been suggested that this device was used by priests to perform useful work such as opening temple doors and moving statues to impress gullible worshippers but no physical evidence remains and these ideas were never developed and the aeolipile remained as a toy. Hero is also credited as being the first to propose a formal way of calculating square roots. Some time between A. In it he summarised the all known information about astronomy and the mathematics which supported the theories.

For over a thousand years it was the accepted explanation of the workings of the Universe. Unfortunately it was based on a geocentric model with uniform circular motions of the Sun and planets around the Earth. Where this ideal motion did not fit the observed movements, the anomalies were explained by the concept of equants with the planets moving in smaller epicyclic orbits superimposed on the major orbit. It was not until Copernicus came along years later that Ptolemy's theory was seriously challenged.

The Almagest was however a major source of information about Greek trigonometry. In a similar vein to the Almagest, Ptolemy also published Geographia which summarised all that was known at the time about the World's geography as well as the projections used to create more accurate maps. Galen carried out controlled experiments to support his theories and was the first to conclude that mental actively occurred in the brain rather than the heart, as Aristotle had suggested.

Like many ancient philosophers his authority was virtually undisputed for many years after his death, thus discouraging original investigation and hampering medical progress until the 16th century.

The first recorded woman in science, she is considered to be the inventor of the hydrometer , called the aerometer by the Greeks. Claims that she also invented the planar astrolabe are probably not true since there is evidence that the astrolabe dates from years earlier, but her mathematician father Theon of Alexandria had written a treatise on the device and she no doubt lectured about its use for calculating the positions of the Sun, Moon and stars.

Hypatia still held pagan beliefs at a time when the influence of Christianity was beginning to grow and unfortunately her science teachings were equated with the promotion of paganism. In she was attacked by a Christian mob who stripped her, dragged her through the streets, killed her and cut her to pieces using oyster shells.

Judging from her appearance as depicted by Victorian artists, it's no surprise that the local monks were outraged. See Hypatia by Charles William Mitchell. In his book "City of God" he uses the example of magnetic phenomena to defend the idea of miracles. Magnetism could not be explained but it manifestly existed, so miracles should not be dismissed just because they could not be explained.

Several tidal mills were built during the Roman occupation of England for grinding grain and corn. They operated by storing water behind a dam during high tide, and letting it out to power the mill after the tide had receded and were the forerunners of the modern schemes for capturing tidal energy.

A pattern of rows of tiny dots was made in a sheet of paper which was pressed down on top of a blank sheet and ink was forced through the holes. Later stencils developed by the Chinese and Japanese used human hair or silk thread to tie delicate isolated parts into the general pattern but there was no fabric backing to hold the whole image together.

The stencil image was printed using a large soft brush, which did not damage the delicate paper pattern or the fine ties. These printing techniques of composite inked squeezes and stencils foreshadowed modern silk screen printing which was not patented until From A. Chemistry Arabic Al Khimiya "pour together", "weld" was indeed the invention of the Muslims who carried out pioneering work over three centuries putting chemistry to practical uses in the refinement of metals, dyeing, glass making and medicine.

In those days the notion of alchemy also included what we would today call chemistry. By the tenth century however, according to historian Toby Huff , the preeminence of Islamic science began to wane.

It had flourished in the previous three centuries while Muslims were in the minority in the Islamic regions however, starting in the tenth century, widespread conversion to Islam took place and as the influence of Islam increased, so the tolerance of alternative educational and professional institutions and the radical ideas of freethinkers decreased. They were dealt a further blow in , thirty five years after the invention of the printing press , when the Ottoman Sultan Byazid II issued an order forbidding the printing of Arabic letters by machines.

Arabic texts had to be translated into Latin for publication and this no doubt hampered both the spread of Islamic science and ideas as well as the influence of the outside world on the Islamic community. This prohibition of printing was strictly enforced by subsequent Ottoman rulers until when the first printing press was established in Istanbul but due to objections on religious grounds it closed down in and the first Koran was not printed in Istanbul until Islam was not alone in banning the dissemination of subversive or inconvenient ideas.

Henry VIII in , aware of the power of the press, became the first monarch to publish a list of banned books though he did not go so far as banning printing. He was later joined by others. Despite these setbacks, European scientific institutions overcame the challenges by the church, taking over the flame carried by the Arabs and the sixteenth and seventeenth centuries became the age of Scientific Revolution in Europe. In the period around A. He isolated or prepared several chemical compounds for the first time, notably nitric, hydrochloric, citric and tartaric acids and published a series of books describing his work which were used as classic works on alchemy until the fourteenth century.

Unfortunately the books were added to, under Geber's name, by various translators in the intervening period leading to some confusion about the extent of Geber's original work. He also introduced the decimal system of Hindu-Arabic numerals to Europe as well as the concept of zero , a mathematical device at the time unknown in Europe used to Roman numerals. Al-Khawarizmi also constructed trigonometric tables for calculating the sine functions.

The word algorithm algorizm is named after him. Around that year, a book attributed to Chinese alchemist Cheng Yin warns of the dangerous incendiary nature of mixtures containing saltpetre potassium nitrate , and sulphur, both essential components of gunpowder. Such chemicals mixed with various other substances including carbonaceous materials and arsenic had been used in various concentrations by alchemists since around A.

After Cheng Yin's warning, similar mixtures were soon developed to produce flares and fireworks as well as military ordnance including burning bombs and fuses to ignite flame throwers burning petrol gasoline. The first example of a primitive gun called a "fire arrow" appeared in , and in , arrows tipped with burning "fire chemicals" were used to besiege the city of Tzu-t'ung.

It was not until that the full power of the saltpetre rich mixture was discovered and the first true formula for gunpowder was published by Tseng Kung-Liang. After that, true explosive devices were developed including cannon and hand grenades and land mines. Around it was realised that an arrow could be made to fly without the need for a bow by attaching to the shaft, a bamboo tube packed with a burning gunpowder mix.

This led to the development of the rocket which was born when larger projectiles were constructed from the bamboo sticks alone without the arrows. A text from around that time describes how the combustion efficiency and hence the rocket thrust could be improved by creating a cavity in the propellant along the centre line of the rocket tube to maximise the burning surface - a technique still used in solid fuelled rockets today.

In Chinese chronicler Chao Yu-Jung recorded the first use of bombs which we would recognise today, with cast iron casings packed with explosives, which created deadly flying shrapnel when they exploded. They were used to great effect by a special catapult unit in Genghis Khan 's Mongol army and by the Chinese Jin forces to defeat their Song enemies in the siege of Kaifeng.

He also prepared ethanol, which was used for medicinal applications, and described how to prepare alkali Al-Qali, the salt work ashes, potash from oak ashes. Al-Razi published his work on alchemy in his " Book of Secrets ". The precise amounts of the substances he specified in his recipes demonstrates an understanding of what we would now call stoichiometry.

Several more words for chemicals are derived from their Arabic roots including alcohol Al Kuhl" "essence", usually referring to ethanol as well as arsenic and borax. Compass needles were made by heating a thin piece of iron, often in the shape of a fish, to a temperature above the Curie Point then cooling it in line with the Earth's magnetic field.

Although his designs achieved widespread use in China, it was another four hundred years before the printing press was "invented" by Johann Gutenberg in Europe.

Challenging Aristotle now became a challenge to the Church. He discovered that a magnet had two magnetic poles , North and South and was the first to describe the phenomena of attraction and repulsion.

He also speculated that these forces could be harnessed in a machine. Paul's in London. The invention of the verge and foliot escapement was an important breakthrough in measuring the passage of time allowing the development of mechanical timepieces. The name verge comes from the Latin virga , meaning stick or rod. See picture and explanation of the Verge Escapement. The inventor of the verge escapement is not known but we know that it dates from 13th century Europe, where it was first used in large tower clocks which were built in town squares and cathedrals.

The earliest recorded description of an escapement is in Richard of Wallingford 's manuscript Tractatus Horologii Astronomici on the clock he built at the Abbey of St. It was not a verge, but a more complex variation. For over years the verge was the only escapement used in mechanical clocks until alternative escapements started to appear in the 16th century and it was years before the more accurate pendulum clock was invented by Huygens.

When the Ming dynasty came into power, China was the most advanced nation on Earth. During the Dark Ages in Europe, China had already developed cast iron , the compass , gunpowder , rockets , paper , paper money, canals and locks, block printing and moveable type , porcelain, pasta and many other inventions centuries before they were "invented" by the Europeans. From the first century B. They were so far ahead of Europe that when Marco Polo described these wondrous inventions in on his return to Venice from China he was branded a liar.

China's innovation was based on practical inventions founded on empirical studies, but their inventiveness seems to have deserted them during the Ming dynasty and subsequently during the Qing Ching dynasty - China never developed a theoretical science base and both the Western scientific and industrial revolutions passed China by.

Why should this be? It is said that the answer lies in Chinese culture, to some extent Confucianism but particularly Daoism Taoism whose teachings promoted harmony with nature whereas Western aspirations were the control of nature.

However these conditions existed before the Ming when China's innovation led the world. A more likely explanation can be found in China's imperial political system in which a massive society was rigidly controlled by all-powerful emperors through a relatively small cadre of professional administrators Mandarins whose qualifications were narrowly based on their knowledge of Confucian ideals.

If the emperor was interested in something, it happened, if he wasn't, it didn't happen. The turning point in China's technological dominance came when the Ming emperor Xuande came to power in Admiral Zheng He , a muslim eunuch, castrated as a boy when the Chinese conquered his tribe, had recently completed an audacious voyage of exploration on behalf of a previous Ming emperor Yongle to assert China's control of all of the known world and to extract tributary from its intended subjects.

But his new master considered the benefits did not justify the huge expense of Zheng's fleet of 62 enormous nine masted junks and smaller supply ships with their 27, crew. The emperor mothballed the fleet and henceforth forbade the construction of any ships with more than two masts, curbing China's aspirations as a maritime power and putting an end to its expansionist goals, a xenophobic policy which has lasted until modern times.

The result was that during both the Ming and the Qing dynasties a succession of complacent, conservative emperors cocooned in prodigious, obscene wealth, remote even from their own subjects, lived in complete isolation and ignorance of the rest of the world. Foreign influences, new ideas, and an independent merchant class who sponsored them, threatened their power and were consequently suppressed. By contrast the West was populated by smaller, diverse and independent nations competing with each other.

Merchant classes were encouraged and innovation flourished as each struggled to gain competitive or military advantage. Times have changed. Currently China is producing two million graduates per year, sixty percent of which are in science and technology subjects, three times as many as in the USA.

For the first time knowledge and ideas could be recorded and disseminated to a much wider public than had previously been possible using hand written texts and its use spread rapidly throughout Europe. Intellectual life was no longer the exclusive domain of the church and the court and an era of enlightenment was ushered in with science, literature, religious and political texts becoming available to the masses who in turn had the facility to publish their own views challenging the status quo.

It was the ability to publish and spread one's ideas that enabled the Scientific Revolution to happen. Nowadays the Internet is bringing about a similar revolution. Although it was new to Europe, the Chinese had already invented printing with moveable type four hundred years earlier but, because of China's isolation, these developments never reached Europe.

Gutenberg printed Bibles and supported himself by printing indulgences, slips of paper sold by the Catholic Church to secure remission of the temporal punishments in Purgatory for sins committed in this life.

He was a poor businessman and made little money from his printing system and depended on subsidies from the Archbishop of Mainz. Because he spent what little money he had on alcohol, the Archbishop arranged for him to be paid in food and lodging, instead of cash. Gutenberg died penniless in It was a law designed more to protect the economy of the state than the rights of the inventor since, as the result of its declining naval power, Venice was changing its focus from trading to manufacturing.

The Republic required to be informed of all new and inventive devices, once they had been put into practice, so that they could take action against potential infringers.

One of the most brilliant minds of the Italian Renaissance, Leonardo was hugely talented as an artist and sculptor but also immensely creative as an engineer, scientist and inventor. The fame of his surviving paintings has meant that he has been regarded primarily as an artist, but his scientific insights were far ahead of their time. He investigated anatomy, geology, botany, hydraulics, acoustics, optics, mathematics, meteorology, and mechanics and his inventions included military machines, flying machines, and numerous hydraulic and mechanical devices.

He lived in an age of political in-fighting and intrigue between the independent Italian states of Rome, Milan, Florence, Venice and Naples as well as lesser players Genoa, Siena, and Mantua ever threatening to degenerate into all out war, in addition to threats of invasion from France.

In those turbulent times da Vinci produced a series of drawings depicting possible weapons of war during his first two years as an independent. Thus began a lifelong fascination with military machines and mechanical devices which became an important part of his expanding portfolio and the basis for many of his offers to potential patrons, the heads of these belligerent, or fearful, independent states.

Despite his continuing interest in war machines, he claimed he was not a war monger and he recorded several times in his notebooks his discomfort with designing killing machines. Nevertheless, he actively solicited such commissions because by then he had his own pupils and needed the money to pay them.

Most of Leonardo's designs were not constructed in his lifetime and we only know about them through the many models he made but mostly from the 13, pages of notes and diagrams he made in which he recorded his scientific observations and sketched ideas for future paintings, architecture, and inventions.

Unlike academics today who rush into publication, he never published any of his scientific works, fearing that others would steal his ideas. Patent law was still in its infancy and difficult, if not impossible, to enforce. Such was his paranoia about plagiarism that he even wrote all of his notes, back to front, in mirror writing, sometimes also in code, so he could keep his ideas private.

He was not however concerned about keeping the notes secret after his death and in his will he left all his manuscripts, drawings, instruments and tools to his loyal pupil, Francesco Melzi with no objection to their publication. Melzi expected to catalogue and publish all of Leonardo's works but he was overwhelmed by the task, even with the help of two full-time scribes, and left only one incomplete volume, "Trattato della Pintura" or "Treatise on Painting", about Leonardo's paintings before he himself died in On his death the notes were inherited by his son Orazio who had no particular interest in the works and eventually sections of the notes were sold off piecemeal to treasure seekers and private collectors who were interested more in Leonardo's art rather than his science.

Because of his secrecy, his contemporaries knew nothing of his scientific works which consequently had no influence on the scientific revolution which was just beginning to stir.

It was about two centuries before the public and the scientific community began gradually to get access to Leonardo's scientific notes when some collectors belatedly allowed them to be published or when they ended up on public display in museums where they became the inspiration for generations of inventors. Unfortunately, only pages are known to survive and over pages of these priceless notebooks have been lost forever.

Who knows what wisdom they may have contained? Leonardo da Vinci is now remembered as both "Leonardo the Artist" and "Leonardo the Scientist" but perhaps "Leonardo the Inventor" would be more apt as we shall see below. It would not do justice to Leonardo to mention only his scientific achievements without mentioning his talent as a painter. His true genius was not as a scientist or an artist, but as a combination of the two: an "artist-engineer".

He did not sign his paintings and only 24 of his paintings are known to exist plus a further 6 paintings whose authentication is disputed. He did however make hundreds of drawings most of which were contained in his copious notes. This was the volume of Leonardo's manuscripts transcribed and compiled by Melzi. The engravings needed for reproducing Leonardo's original drawings were made by another famous painter, Nicolas Poussin. As the title suggests it was intended as technical manual for artists however it does contain some scientific notes about light, shade and optics in so far as they affect art and painting.

For the same reason it also contains a small section of Leonardo's scientific works about anatomy. The publication of this volume in was the first time examples of the contents of Leonardo's notebooks were revealed to the world but it was years after his death. The full range of his "known" scientific work was only made public little by little many years later. Leonardo was one of the world's greatest artists, the few paintings he made were unsurpassed and his draughtsmanship had a photographic quality.

Just seven examples of his well known artworks are mentioned here. After serving his apprenticeship with Verrocchio, Leonardo had a continuous flow of military commissions throughout his working life. In the ruthless and murderous Cesare Borgia , illegitimate son of Pope Alexander VI and seducer of his own younger sister Lucrezia Borgia , appointed Leonardo as military engineer to his court where he became friends with Niccolo Machiavelli , Borgia's influential advisor.

These commissions gave Leonardo ample scope to develop his interest in military machines. Leonardo designed war machines for both offensive and defensive use. They were designed to provide mobility and flexibility on the battlefield which he believed was crucial to victory.

He also designed machines to use gunpowder which was still in its infancy in the fifteenth century. They included a triple barrelled cannon and an eight barrelled gun with eight muskets mounted side by side as well as a 33 barrelled version with three banks of eleven muskets designed to enable one set of eleven guns to be fired while a second set cooled off and a third set was being reloaded.

The banks were arranged in the form of a triangle with a shaft passing through the middle so that the banks could be rotated to bring the loaded set to the top where it could be fired again.

Leonardo studied the flight of birds and after the legendary Icarus was one of the first to attempt to design human powered flying machines, recording his ideas in numerous drawings. A step up from Chinese kites.

The following are examples of some of the tools and scientific instruments designed by da Vinci which were found in his notes. As part of his training in Veroccio's studio, like any artist, Leonardo studied anatomy as an aid to figure drawing, however starting around and later with the doctor Marcantonio della Torre he made much more in depth studies of the body, its organs and how they function. Because the bulk of his work was not published for over years, his observations could possibly have prompted an earlier advance in medical science had they been made available during his lifetime.

At least his drawings provided a useful resource for future students of anatomy. Leonardo had an insatiable curiosity about both nature and science and made extensive observations which were recorded in his notebooks. He did not however develop any new scientific theories or laws. Instead he used the knowledge gained from his observations to improve his skills as an artist and to invent a constant stream of useful machines and devices.

Leonardo unquestionably had one of the greatest inventive minds of all time, but very few of his designs were ever constructed at the time. The reason normally given is that the technology didn't exist during his lifetime. With his skilled draughtsmanship, Leonardo's designs looked great on paper but in reality many of them would not actually work in practice, an essential criterion for any successful invention, and this has since been borne out by subsequent attempts to construct the devices as described in his plans.

This should not however detract in any way from Leonardo's reputation as an inventor. His innovations were way ahead of their time, unique, wide ranging and based on sound engineering principles. What was missing was the science.

At least he had the benefits of Archimedes ' knowledge of levers, pulleys and gears, all of which he used extensively, but that was the limit of available science. Newton's Laws of Motion were not published until two centuries after Leonardo was working on his designs. The science of strength of materials was also unheard of until Newton's time when Hooke made some initial observations about stress and strain and there was certainly no data available to Leonardo about the engineering properties of materials such as tensile, compressive, bending and impact strength or air pressure and the densities of the air and other materials.

Torricelli's studies on air pressure came about fifty years before Newton, and Bernoulli's theory of fluid flow , which describe the science behind aerodynamic lift, did not come till fifty 50 years after Newton.

But, even if the science had existed, Leonardo lacked the mathematical skills to make the best of it. So it's not surprising that Leonardo had to make a lot of assumptions. This did not so much affect the function of his mechanisms nor the operating principle on which they were based, rather it affected the scale and proportions of the components and the force or power needed to operate them.

His armoured tank would have been immensely heavy and difficult to manoeuvre, and it's naval version would have sunk unless its buoyancy was improved. The wooden gears used would probably have been unable to transmit the enormous forces required to move these heavy vehicles. The repeated recoil forces on his multiple-barrelled guns may have shattered their mounts, and his flying machines were very flimsy with inadequate area of the wings as well as the level of human power needed to keep them aloft.

So there was nothing fundamentally wrong with most of his designs and most of the shortcomings could have been overcome with iterative development and testing programmes to refine the designs. Unfortunately Leonardo never had that opportunity. Leonardo was indeed a genius but his reputation has also been enhanced or distorted by uncritical praise. Speculation, rather than firm evidence, about the performance of some of the mechanisms mentioned in his notebooks and what may have been in the notebooks which have been lost, has incorrectly credited him with the invention of the telescope, mathematical calculating machines and the odometer to name just three examples.

Though he did experiment with optics and made drawings of lenses, he never mentioned in his notes, a telescope, or what he may have seen with it, so it is highly unlikely that he invented the telescope. As for his so called calculating machine: It looked very similar to the calculator made by Pascal years later but it was in fact just a counting machine since it did not have an accumulator to facilitate calculations by holding two numbers at a time in the machine as in Pascal's calculator.

Leonardo's "telescope" and "calculating machine" are examples of uninformed speculation from tantalising sketches made, without corresponding explanations, in his notes. Such speculation is based on the reasoning that, if one of his sketches or drawings "looks like" some more recent device or mechanism, then it "must be" or actually "is" an early example of such a device. Leonardo already had a well deserved reputation as a genius without this unnecessary gold plating.

Similarly regarding the odometer: The claim by some, though not by Leonardo himself, that he invented the odometer implies that he was the first to envisage the concept of an odometer. The odometer was in fact invented by Vitruvius 15 centuries earlier.

Leonardo invented "an" odometer, not "the" odometer. Many inventions are simply improvements, alternatives or variations, of what went before. Without a knowledge of precedents, it is a mistake to extrapolate a specific case to a general conclusion.

Leonardo's design was based on measuring the rotation of gear wheels, whereas Vitruvius' design was based on counting tokens. Note that Vitruvius also mentions in his "Ten Books on Architecture" , designs for trebuchets, water wheels and battering rams protected by mobile siege sheds or armoured vehicles which were called "tortoises".

It is rare to find an invention which depends completely on a unique new concept and many perfectly good inventions are improvements or alternatives to prior art. This applies to some of Leonardo's inventions just as it does to the majority of inventions today.

Nobody would or should claim that Leonardo invented the clock when his innovation was to incorporate a new mechanical movement into his own version of a clock, nor should they denigrate his actual invention. It's a great pity that Leonardo kept his works secret and that they remained unseen for so many years after his death. How might technology have advanced if he had been willing to share his ideas, to explain them to his contemporaries and to benefit from their comments?

The Crown thus started making specific grants of privilege to favoured manufacturers and traders, signified by Letters Patent , open letters marked with the King's Great Seal. The system was open to corruption and in the Statute of Monopolies was enacted to curb these abuses.

It was a fundamental change to patent law which took away the rights of the Crown to create trading monopolies and guaranteed the inventor the legal right of patents instead of depending on the royal prerogative. So called patent law , or more generally intellectual property law , has undergone many changes since then to encompass new concepts such as copyrights and trademarks and is still evolving as and new technologies such as software and genetics demand new rules.

Indeed it had even been reinforced in the thirteenth century by St. Thomas Aquinas who proclaimed the unity of Aristotelian philosophy with the teachings of the church. The credibility of new scientific ideas was judged against the ancient authority of Aristotle , Galen , Ptolemy and others whose science was based on rational thought which was considered to be superior to experimentation and empirical methods.

Challenging these conventional ideas was considered to be a challenge to the church and scientific progress was hampered accordingly.

In medieval times, the great mass of the population had no access to formal education let alone scientific knowledge. Their view of science could be summed up in the words of Arthur C.

Clarke , "Any sufficiently advanced technology is indistinguishable from magic". Things began to change after when a few pioneering scientists discovered, and were able to prove, flaws in this ancient wisdom. Once this happened others began to question accepted scientific theories and devised experiments to validate their ideas. In the past, such challenges had been hampered by the lack of accurate measuring instruments which had limited the range of experiments that could be undertaken and it was only in the seventeenth century that instruments such as microscopes, telescopes, clocks with minute hands, accurate weighing equipment, thermometers and manometers started to become available.

Experimenters were then able to develop new and more accurate measurement tools to run their experiments and to explore new scientific territories thus accelerating the growth of new scientific knowledge. The printing press was the great catalyst in this process. Scientists could publish their work, thus reaching a much greater audience, but just as important, it gave others working in the field, access to the latest developments.

It gave them the inspiration to explore these new scientific domains from a new perspective without having to go over ground already covered by others. The increasing use of gunpowder also had its effect. Cannons and hand held weapons swept the aristocratic knight from the field of battle. Military advantage and power went to those with the most effective weapons and heads of state began to sponsor experimentation in order to gain that advantage. Scientific method thus replaced rational thought as a basis for developing new scientific theories and over the next years scientific theories and scientific institutions were transformed, laying the foundations on which the later Industrial Revolution depended.

The Age of Reason marked the triumph of evidence over dogma. Or did it? There remained one great mystery yet to be unravelled but it was another years before it came up for serious consideration: The Origin of Species. Such heresies were unthinkable at the time. They not only contradicted conventional wisdom that the World was the centre of the universe but worse still they undermined the story of creation, one of the fundamental beliefs of the Christian religion.

Dangerous stuff! It was not until around that Copernicus completed the work which he called De Revolutionibus Orbium Coelestium " On the Revolutions of the Heavenly Spheres " but he still declined to publish it.

Historians do not agree on whether this was because Copernicus was unsure that his observations and his calculations would be sufficiently robust enough to challenge Ptolemy's Almagest which had survived almost years of scrutiny or whether he feared the wrath of the church. Copernicus' model however was simpler than Ptolemy's geocentric model and matched more closely the observed motions of the planets.

He eventually agreed to publish the work at the end of his life and the first printed copy was reportedly delivered to him on his deathbed, at the age of seventy, in As it turned out, "De Revolutionibus Orbium Coelestium" was put on the Catholic church's index of prohibited books in , as a result of Galileo's support for its revolutionary theory, and remained there until One of the most important books ever written, De Revolutionibus' ideas ignited the Scientific Revolution See above , but only about or were printed and it became known recently as "the book that nobody read".

Because it was often inconvenient or difficult to measure large distances directly, he described how the distance to a distant target location could be determined locally, without actually going there, by using only angle measurements. By forming triangles to the target from reference points on a local baseline, and measuring the angles between the baseline and the lines between the reference points and the target at the vertex of the triangle, the distance to the target could be calculated using simple trigonometry.

It was thus easier to survey the countryside and construct maps by dividing the area into triangles rather than squares. This method was first used in B. Triangulation is still used today in applications from surveying to celestial navigation. In Frisius was also the first to describe how longitude could be determined by comparing local solar time with the time at some reference location provided by an accurate clock but no such clocks were available at the time.

He carried out his research on the corpses of executed criminals and discovered that the research and conclusions published by the previous, undisputed authority on this subject, Galen , could not possibly have been based on an actual human body. Versalius was one of the first to rely on direct observations and scientific method rather than rational logic as practiced by the ancient philosophers and in so doing overturned years of conventional wisdom.

In the early '90s, Delta bough the Acme National subsidiary of R. Also beginning in the early s, Lindquist Machine corp. In , Delta bought rip-fence maker Biesemeyer Manufacturing Corp. In , the two divisions were formally merged. The new company is Delta Power Equipment Corp. Delta provides owners manuals and parts lists for a variety of machines, including many of those from the Rockwell and Homecraft lines.

Check the Delta website first; some manuals are available there for free download. Be sure to have either a model number or serial number handy. There is a small fee for manuals sent by mail. Be sure to check out the "Publication Reprints" tab, above, where you will find a list of over manuals and catalogs covering the entire history of Delta, from the s to the present. Well, there isn't much information past the mids but Delta can provide information on those more recent machines. Delta mostly made their own products, but especially in the early years they sometimes OEM'd machines from other makers.

For example, Delta's No. And the Model 6" old-style bench grinder was made by Doerr Electric Corp. Register :: Login. Home Page. Mission Submitting Content VintageMachinery. Classified Ads Vintage Machinery Store. Photo: David Sampar Restored 6x48 belt sander from Keith's history article also provides information on specific product: when they were introduced, and how they changed over the years.

The history of Delta in South Africa. Other Delta articles in the wiki. Paint colors, how to rebuild a scrollsaw air pump, a type study of Delta cast-iron stands, information specific to bandsaw, lathes, Unisaws, and more. Keith Bohn's Delta miter gauge type study. Delta History —History of the company from the Delta Machinery web site. Some of these facts are in dispute.

Plaza Machinery —Delta Accessories and Parts. Rebuilding A Rockwell Tablesaw —A nice article on just just what the title says. Delta-branded Products from Other Makers Delta mostly made their own products, but especially in the early years they sometimes OEM'd machines from other makers. Information Sources Thanks to Keith Bohn and many other members of the Old Woodworking Machines forum for contributing almost all of the information here.

Milwaukee, Wis. The following month, the ad read, simply, "Delta Manufacturing Co. Further information on the January sale came from an article on the Fine Woodworking website. The buyer is Chang Type Industrial Co. Joe Potter provided information from his notes, including the exact date for the sale of the woodworking machinery line to Pentair.

A history page on the Delta website claims that Pentair bought Delta from Rockwell in This assertion is contradicted by the evidence above. Please contact us if you can provide more solid evidence one way or the other. Our purpose is to provide information about vintage machinery that is generally difficult to locate. Catalogs, manuals and any other literature that is available on this site is made available for a historical record only.

Please remember that safety standards have changed over the years and information in old manuals as well as the old machines themselves may not meet modern standards. It is up to the individual user to use good judgment and to safely operate old machinery.

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