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Home , Classical element

EVOLUTION OF —Part 1

P. N. Thankachan∗

HE EARLIEST applications of chemical highest priority followed by , and Tprocesses were concerned with the ex- . He linked the four elements to the traction and working of metals and man- social hierarchy of different classes. In In- ufacture of pottery. These arts were car- dia, five elements: earth, water, fire, air and ried without any theoretical knowledge, but ether, were supposed to be the basic ele- often with considerable skill. A survey of ments. the industrial activities of the ancient na- tions shows that the technical arts of the classical period in Greece and Rome are The dawn of Western alchemy is some- really decadent forms of crafts practised times associated with that of metallurgy, by Bronze Age cultures. The copper tools extending back to 3500 BC. Many writ- and utensils had been extensively used by ings were lost when the emperor Diocletian Sumerians and Indians. ordered the burning of alchemical books after suppressing a revolt in Alexandria Classical Concept of Materials (292 AD). Few original Egyptian documents Like other branches of knowledge, the on alchemy have survived, most notable knowledge in chemistry also underwent among them are the Stockholm papyrus an evolutionary process. This was from and the Leyden papyrus X. Dating from AD the primitive materialistic stage, through 300 to 500; they contained recipes for dye- the mystic, and finally to the scientific ing, making artificial gemstones, cleaning stage. For example, in Greece, the Ionian and fabricating pearls and the manufacture philosophers like Thales and ex- of imitation gold and silver. These writings pounded a materialistic outlook of nature. lack the mystical, philosophical elements of They thought water and air were the ba- alchemy. They contain the works of Bolus sic forms of , from which everything of Mendes which aligned these recipes with evolves. Heraclitus conceived a dynamic, and the Classical element. Be- ever changing material world. Empedo- tween the time of Bolus (fourth century BC) cles suggested the ‘four elements’ theory and of fourth century whereby all forms of matter has air, water, AD, the change took place that transformed fire and earth as their basic constituents. It this metallurgy into a Hermetic art. was who attributed the hierarchi- Alexandria acted as a melting pot for cal order for the four elements. with of Pythagoreanism, Platonism, and Gnosticism which shaped the ∗The author is a member of the Kerala state chap- character of alchemy. An important exam- ter of Breakthrough Science Society . He is currently ple of alchemy’s roots in Greek working as Associate Professor, Dept. of Electronics and Communication, Rajiv Gandhi Institute of Tech- originated by and developed by nology, Kottayam. Aristotle, was that everything in the uni-

Breakthrough, Vol.15, No.2, October 2011 1 General Article verse was supposed to be formed from only four elements: earth, air, water, and fire. According to Aristotle, each element had a sphere to which it belonged and to which it would return if left undisturbed. The four elements of the Greek were mostly qualita- tive aspects of matter, not quantitative, as our modern elements are. Though Greeks were much ahead in cultivating philosophy, the actual knowledge in chemistry matured somewhere else, in Alexandria, after its in- vasion by Alexander. Alchemy developed further with the Arabs. Since all matter was thought to be made from the primary matter hule and to be composed of the four elements combined in varying proportions, the Alexandrian chemists concluded that all substances are convertible and trans- mutable one into another, by adjusting the relative proportions of the four elements. Their attempts to effect what their theory (11 Nov. 1493 – 24 Sept. 1541) predicted failed; and so they made fur- ther supposition, namely, that a special substance, which later came to be known was supposed to contain varying propor- as the ‘Philosopher’s stone’, was necessary tions of all these five elements. A form of to achieve transmutation. When water is was introduced in the Vais- boiled and evaporated, some earthy matter esika system, attributed to Kanada. Indian was left; and it seemed that water was con- Alchemy (Rasasidddhi, “knowledge of mer- vertible to earth. When a steel knife was cury”) dates from 5th century AD. In India dipped in a ‘blue stone’ or copper sulphate chemistry was very much associated with solution, copper coating is produced on the . Old Indian medical works are knife. The inference was that could be the Bower Manuscript (4th century AD) and transmuted to copper. This resulted in a the treatises attributed to Caraka (AD 100) natural quest: Why cannot all substances and Susrtha (AD 200). India produced good be transmuted into gold by a suitable chem- iron, the famous Delhi Pillar, weighing 6.5 ical process? People attempted to do that tons, of forged (not cast) iron, was made in in various ways, which has a long his- AD 415. tory. Though chemistry did not grow much through these attempts, some progress was Chemistry in the middle ages made in the methods, and the use and de- sign of apparatuses. The stagnation and the static view persisted through the middle ages not only in chem- In India the Samkhya system of philos- istry, but in all fields of knowledge. The ophy, ascribed to Kapila (550 BC?) de- biblical concepts interpreted by the famous scribes five elements: ether, air, fire, wa- clergyman Thomas Aquinas were the last ter, and earth. Each natural element word in all . Thomas Aquinas re-

2 Breakthrough, Vol.15, No.2, October 2011 General Article lated the heavenly to the human being and nature. This worldview, though static, was comprehensive. The conception of uni- verse with earth as the centre and the heav- enly bodies revolving round it was devel- oped. The remain static in the uni- verse. Different angels were believed to con- trol the . They also had hierarchi- cal positions. The lowest one residing on controls the bottom level, the earthly matters. Everything was supposed to be composed of the four elements, with fire at the helm, followed by air, water and earth.

Roger Bacon was the foremost among the later middle age philosophers to throw (January 25, 1627 – some on the dark picture. The wave December 30, 1691) of started in Italy in the 16th century. Copernicus and Bruno questioned the geocentric model of universe. In chem- The birth of modern chemistry istry Paracelsus’ name figures in the 16th century. He burned the books of the doctor In the 17th century, the scientific endeav- in public and tried to link theory and ours took a definite turn. Instead of follow- practice in Medicine. He added three prin- ing Aristotle or the Holy Scriptures blindly, ciples: sulphur, and salt, to the scientists started enquiring about the phe- four elements. He made chemistry a part nomena around them with their own sense of medicine () but ultimately organs. Many of the truths revealed were he himself fell to more mystic propositions contradictory to the old concepts. They dis- with different in the . covered and proved the findings through experiments. had been drawn be- tween metals of Alchemy and astronomical Though Galileo was put under ar- bodies. Hence the fall of Alchemy was im- rest, and had to submit to the church, the minent due to the victory of the Copernican ‘Two New Sciences’ published in 1642 in model over the geocentric model of the uni- Leiden and his other works attracted the verse. attention of the scholars of . New- Robert Boyle was a contemporary of Isaac ton was born in the same year Galileo died. Newton. Instead of simply following the four New was blowing in Europe. The element theory, he ventured to do exper- law of gravitational was suggested in 1666. iments, especially on the . He later Robert Hooke also postulated the inverse published the book, “Sceptical Chemist.” square law. In every field of knowledge, new Boyle launched a criticism of the current wave of thought started evolving. It was beliefs in the theories of the four elements Luther in Germany to start a new stream and the three principles. He especially in prose. It was Raphael and Leonardo in attacked and refuted the underlying as- Painting. Robert Boyle did it in chemistry. sumptions of these theories by facts drawn

Breakthrough, Vol.15, No.2, October 2011 3 General Article the phlogiston theory. They said that all combustible bodies contain an entity called phlogiston. The more the content of Phlo- giston, the better it burns. When the body burns, the Phlogiston comes out. Subse- quently it was found that when calx (ox- ides of metals) was formed by heating met- als, the weight was increased. This con- tradicted the phlogiston theory that some- thing is given out when burning process happens. To answer this, phlogiston was supposed to be a levitating (negative grav- ity) material. We now know that it is oxida- tion taking place during combustion. But Joseph Priestly, who discovered , was a believer of Phlogiston theory. This prevented him from seeing that it was an Robert Hooke (28 July 1635 – 3 March element. The Phlogiston theory delayed the 1703) growth of chemistry by almost one century.

The revolution in dynamics from well known observations in chemistry. Boyle urged the chemists to examine facts With the growth of mining, scientists be- closely and to fit their theory to facts. To came interested in the gases in mines. The clear the way, he defined the chemical el- gases causing explosion in mines, the dan- ements as “an element is a substance that cannot be decomposed into anything sim- pler ···” Robert Hooke was an assistant to Boyle. He was known as the best experimental scientist before Michael Faraday. He con- structed most of the experimental setups of Boyle. Another name that figures in the same period was John Mayow. Boyle, Hooke and Mayow were called the Oxford Scientists. The last and lethal blow was given by Toricelli, a student of Galileo, by inventing vacuum. But in chemistry the wind blew in another direction.

Phlogiston Theory

Following Paracelsus’ inclusion of sulphur, mercury and salt in the list of ‘elements’, Johann Joachim Becher and Earnst Stall put forward a new theory of combustion— J. J. Becher (1635-1682)

4 Breakthrough, Vol.15, No.2, October 2011 General Article gerous gases in the marshy lands, the poi- sonous gases formed during distillation— the causes of these phenomena were un- known. Van Helmond called these gases ‘ghosts’ for the first time. Stephen Hales showed that these gases could be collected over water. Priestly and Cavendish demon- strated that these could be collected over mercury in a better way. The next step was to understand that these were not merely air but there was qualitative difference be- tween them.

Joseph Black and fixed air

Quantitative experiments are the indis- pensable part in the development of any field of science. For the evolution of clear (13 March 1733 – 6 and comprehensive theories, the evidences February 1804) from quantitative experiments are needed. It was Joseph Black, a doctor from Scot- land, who made the first steps in this direc- Lavoisier and modern chemistry tion. Black collected carbon dioxide (which he called “fixed air”) and weighed it. He Lavoisier did not discover any new ele- could even collect the fixed air and thereby ments. He did not discover any new method proves that the gas could be part of a for producing any new compounds. His and that there was nothing mystic about it. merit is that he arrived at correct conclu- sions from the experiments conducted by other scientists, sometimes repeating the Joseph Priestly and oxygen same in a better quantifiable manner. It has been well said that Lavoisier, though The discovery of oxygen by Joseph Priestly a great architect in science, laboured little in 1774 was another blow to the ‘four el- in the quarry. His materials were chiefly ement’ theory. He showed that this air is shaped to his hand, and his skill was dis- not like ordinary air. Things burned easily played in their arrangement and combi- in the presence of this gas and he called it nation. Lavoisier completed the works of dephlogisticated air. This showed that air, Priestly, Black and Cavendish and gave a which was considered to be one of the four correct explanation of their experiments. ‘elements’, is not a single thing. It contains He conducted many quantitative experi- constituent components like ‘fixed air’ and ments. He used the balance extensively. ‘dephlogisticated air’ which have their own In the experiments of Joseph Black and individual characteristics. By this time, Cavendish, the Law of Conservation of Mass Henry Cavendish announced the discovery was vivid. Lomnosov had already given of hydrogen (inflammable air). hints in that direction. But it was Lavoisier

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Antoine Lavoisier (26 August 1743 – 8 May 1794) who categorically placed the Law of Conser- clusions that a body could burn only in vation of Mass: pure air (oxygen) and thereby made the Phlogiston theory unnecessary. “Nothing is created in the operations He defined the elements as “the final con- either of art or of Nature, and it can dition a chemical analysis can reach.” This be taken as axiom that in every oper- was basically Boyle’s definition. But the ation an equal quantity of matter ex- discovery of oxygen, hydrogen, and carbon ists both before and after the opera- dioxide clearly showed the new elements. tion.” With the repetition of the Cavendish’s ex- Another revolutionary contribution of periment on the synthesis of water from Lavoisier was the new nomenclature in oxygen and hydrogen, the position of wa- chemistry. In the eighteenth century, ter as element was questioned. Lavoisier, many substances retained the names given continuing the experiments of Black, Priest- to them in classical antiquity, or names ley and Cavendish, conclusively proved that coined from their appearance or properties, at least two elements of Alchemy—the air or from the place of their discovery or oc- and water, had the component elements currence, or from some superficial resem- and were actually or compounds. blance to a familiar substance. Instead of Hence Alchemy could not survive after that the name given by Lavoisier to a sub- Lavoisier. He made Phlogiston theory un- stance was designed to indicate its chemi- necessary in Chemistry. Lavoisier defined cal composition. The names oxygen, hydro- the Law of . With the gen, etc. were given by Lavoisier. introduction of the new style of nomencla- Through carefully conducted experiments ture, modern chemistry grew as a system of on combustion, Lavoisier came to the con- knowledge after Lavoisier. 2

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