The opening chapters present empirical arguments for the basic cosmological framework within which Ptolemy worked. Earthhe argued, is a stationary sphere at the centre of a vastly larger celestial sphere that revolves at a perfectly uniform rate around Earth, carrying with it the starsplanetsSunand Moon —thereby causing their daily risings and settings. Through the course of a year the Sun slowly traces out a great circle, known as the eclipticagainst the rotation of the celestial sphere. The fundamental assumption of the Almagest is that the apparently irregular movements of the heavenly bodies are in reality combinations of regular, uniform, circular motions.
The only biographical information known about him is contained in his famed Book of Knowledge of Ingenious Mechanical Devices.
According to Mayr, the book's style resembles that of a modern "do-it-yourself" book. Al-Jazari goes on to describe the improvements he made to the work of his predecessors, and describes a number of devices, techniques and components that are original innovations which do not appear in the works by his precessors.
We see for the first time in al-Jazari's work several concepts important for both design and construction: Segmental gears first clearly appear in al-Jazari, in the West they emerge in Giovanni de Dondi 's astronomical clock finished inand only with the great Sienese engineer Francesco di Giorgio did they enter the general vocabulary of European machine design.
Al-Jazari invented five machines for raising water,  as well as watermills and water wheels with cams on their axle used to operate automata in the 12th and 13th centuries, and described them in It was in these water-raising machines that he introduced his most important ideas and components.
Saqiya chain pumps[ edit ] The first known use of a crankshaft in a chain pump was in one of al-Jazari's saqiya machines. The concept of minimizing intermittent working is also first implied in one of al-Jazari's saqiya chain pumps, which was for the purpose of maximising the efficiency of the saqiya chain pump.
Al-Jazari also constructed a water-raising saqiya chain pump which was run by hydropower rather than manual labourthough the Chinese were also using hydropower for chain pumps prior to him. Saqiya machines like the ones he described have been supplying water in Damascus since the 13th century up until modern times,  and were in everyday use throughout the medieval Islamic world.
This pump is driven by a water wheel, which drives, through a system of gears, an oscillating slot-rod to which the rods of two pistons are attached. The pistons work in horizontally opposed cylinders, each provided with valve-operated suction and delivery pipes.
The delivery pipes are joined above the centre of the machine to form a single outlet into the irrigation system.
This water-raising machine had a direct significance for the development of modern engineering. This pump is remarkable for three reasons: The first application of the double-acting principle. The conversion of rotary to reciprocating motion via the crank-connecting rod mechanism. Al-Jazari's suction piston pump could lift This was more advanced than the suction pumps that appeared in 15th-century Europe, which lacked delivery pipes.
It was not, however, any more efficient than the noria commonly used by the Muslim world at the time. The system had water from a lake turn a scoop-wheel and a system of gears which transported jars of water up to a water channel that led to mosques and hospitals in the city.
Rosheim summarizes the advances in robotics made by Muslim engineers, especially al-Jazari, as follows: Unlike the Greek designs, these Arab examples reveal an interest, not only in dramatic illusion, but in manipulating the environment for human comfort. Thus, the greatest contribution the Arabs made, besides preserving, disseminating and building on the work of the Greeks, was the concept of practical application.
This was the key element that was missing in Greek robotic science. The drink was stored in a tank with a reservoir from where the drink drips into a bucket and, after seven minutes, into a cup, after which the waitress appears out of an automatic door serving the drink.
It features a female humanoid automaton standing by a basin filled with water. When the user pulls the lever, the water drains and the female automaton refills the basin. Rosheim describes it as follows: When more water is used, a second float at a higher level trips and causes the appearance of a second servant figure — with a towel!
Musical robot band[ edit ] Al-Jazari's musical robot band. Al-Jazari's work described fountains and musical automata, in which the flow of water alternated from one large tank to another at hourly or half-hourly intervals. This operation was achieved through his innovative use of hydraulic switching.
Professor Noel Sharkey has argued that it is quite likely that it was an early programmable automata and has produced a possible reconstruction of the mechanism; it has a programmable drum machine with pegs cams that bump into little levers that operated the percussion.
The drummer could be made to play different rhythms and different drum patterns if the pegs were moved around. These included a portable water-powered scribe clockwhich was a meter high and half a meter wide, reconstructed successfully at the Science Museum in   Al-Jazari also invented monumental water-powered astronomical clocks which displayed moving models of the Sun, Moon, and stars.
One of al-Jazari's candle clocks. According to Donald Hillal-Jazari described the most sophisticated candle clocks known to date.
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Hill described one of al-Jazari's candle clocks as follows: Wax collected in the indentation and could be removed periodically so that it did not interfere with steady burning. The bottom of the candle rested in a shallow dish that had a ring on its side connected through pulleys to a counterweight.
As the candle burned away, the weight pushed it upward at a constant speed.summarize the life and work of Leonardo da Vinci ; Leonardo da Vinci: Biography Leonardo da Vinci Lesson Plan Related Study Materials.
Leonardo da Vinci: Leonardo da Vinci, Italian painter, draftsman, sculptor, architect, and engineer whose accomplishments epitomized the Renaissance humanist ideal. His Last Supper (–98) and Mona Lisa (c. –19) are among the most influential paintings of the Renaissance. Read more about Leonardo’s life and career.
Leonardo di ser Piero da Vinci (Italian: [leoˈnardo di ˌsɛr ˈpjɛːro da (v)ˈvintʃi] (listen); 15 April – 2 May ), more commonly Leonardo da Vinci or simply Leonardo, was an Italian polymath of the Renaissance, whose areas of interest included invention, painting, sculpting, architecture, science, music, mathematics, engineering, literature, anatomy, geology, astronomy, botany, writing, history, and .
In this lesson, we will build an outline of the historical events which flow together to form the time periods of the Renaissance, Reformation, Age of Discovery, and the Elizabethan era.
Biography of Leonardo Da Vinci Early life, – Leonardo was born on April 15, , "at the third hour of the night" in the Tuscan hill town of Vinci, in .
Virtually nothing is known about Ptolemy’s life except what can be inferred from his writings. His first major astronomical work, the Almagest, was completed about ce and contains reports of astronomical observations that Ptolemy had made over the preceding quarter of a century.
The size and content of his subsequent literary production suggests that he lived until about ce.