Migration

Part 11 - Chemistry

One of the earliest use of chemistry was in the manufacture of dyes for painting and clothing. Cave painters, in 15,000 BCE, used black, white, yellow, and reddish pigments made from ochre while fabric dyeing dates from at least 10,000 BCE.

In China, black dyes were made from iron sulphate while indigo leaves were the most popular for dark blue, red came from madder root and yellow from Jinzi fruit. Other natural dyes were obtained from plants, like turmeric roots, berries, bark, leaves, flowers and wood or insects, fungi and minerals. 

Most dyes needed to be fixed with metal salts (mordants) such as alum (potassium aluminum sulphate) and iron (ferrous sulphate) but non-metal salts like tannin from oak galls and ammonia from urine were also used.

Plant-based dyes, including woad (Isatis tinctoria), indigo, saffron, alizarin, logwood and madder were valuable trade goods in Europe, Africa and Asia while rare natural dyes, like the brilliant Tyrian purple (extracted from the glands of snails. 12 000 snails produced only 1.4 grams) was a luxury item in the Roman empire.

Indigo was made from the woad herb (isatis tinctoria) and indigofera tinctoria while red dyes like Alizarin were extracted from the madder plant and kermes and cochineal were made from insects.

The Greek philosopher, Empedocles, (492 to 432 BCE) argued that all matter was composed of fire, air, water, and earth in various proportions. He thought stone contained mostly earth, while a rabbit had a more of both fire and water thus giving it life. This was an important theory as it was one of the earliest suggestions that substances, like stone, were a combination of different "elements."

Later, Democritus (460 to 370 BCE), noted that broken pieces of stone never resembled fire, air, water, or earth, and reasoned that cutting a stone into ever smaller pieces would eventual result in pieces too small to be cut. He suggested these infinitesimally small fragments were indestructible and unique for each material and he named them atomos meaning indivisible. Unfortunately, two of the most famous philosophers of Ancient Greece, Aristotle and Plato, rejected Democritus' idea and it was almost 2,000 years before it was rediscovered.

Following the collapse of the Roman empire in the west, knowledge of Greek and Roman science, engineering and philosophy was forgotten in much of Europe, but the great library at Alexandria attracted the attention of Muslim scholars who began translating the works of the ancient Greeks and Egyptians into Arabic and some of them began experimenting.

This was a slow and hit-or-miss task but the scientific method began in the 9th-century with Jābir ibn Hayyān (also known as Geber). He wrote many books in Arabic on a variety of subjects including alchemy, cosmology, numerology, astrology, medicine, magic and philosophy but he was best known as the founder of modern chemistry.

He devised a systematic experimental method based on his laboratory work, unlike the ancient Greek and Egyptian alchemists who ideas were largely speculations. He began with the classical Greek idea of elements that alchemists considered the irreducible elements of the universe. He adopted the four Aristotelian elements of air, earth, fire, and water and added two more elements;- sulphur, (the burning stone) characterizing the principle of combustibility and mercury, characterizing metallic properties.

Jābir ibn Hayyān developed the earliest known classification of chemical substances, and the oldest known set of instructions for extracting inorganic compounds (like sal ammoniac or ammonium chloride) from organic substances (such as plants and blood) using chemical methods.He named the al-anbiq (alembic), a distilling apparatus originating in Ancient Greek consisting of two vessels connected by a tube, and used it to condense mercury vapour and alcohol. He identified and chemically analyzed substances, including many type of rock and gem stones, noting that some were harder than others. He examined the metallic elements known in his day (gold, silver, copper, iron, tin and lead). He distinguished between alkalis and acids, and is credited with the invention of several chemical processes including crystallization, calcinations, sublimation and evaporation, the synthesis of hydrochloric, nitric, citric, acetic and tartaric acids and developed aqua regia (a mixture of nitric acid and hydrochloric acid) to dissolve gold. 

Other Muslim chemists, including Abū al-Rayhān al-Bīrūnī, Al-Kindi and Avicenna, refuted the theories of alchemy, and particularly the idea that one metal could be transmuted into another metals (so gold could not be made from lead).

Al-Tusi noted that a material can be made to change but cannot be made to disappear. This was the beginning of the idea of the conservation of mass.

Abū Bakr Muhammad ibn Zakariyyā al-Rāzī, (also known by his Latinized name Rhazes) (854 to 925 CE), wrote more than 200 books, particularly about advances in medical knowledge but he also was the first to refute Aristotle's theory of the four classical elements thus beginning modern chemistry. He designed and described several instruments such as the crucible, the retort for distillation, and the design of a still with a delivery tube (the alembic), and several types of furnaces. He also discovered many chemical compounds including alcohol and sulfuric acid.

Abu Bakr al-Khwarazmi wrote, "Keys to the Sciences", an early Islamic Encyclopedia about 977 CE. The work included sections on mathematics, alchemy, medicine and meteorology.

There are many English words derived from Arabic words including alchemist, chemist, alcohol, algebra, algorithm, coffee, cotton, magazine, mattress, sofa and zero.

The Italian mathematician Fibonacci grew up in North Africa, and learned the Arabic word sifr, which means empty or nothing. Since the Europeans had no concept of zero when he re-introduced the Indian/Arabic number system to Italy, in the 13th century, he Latinized it to zephrum, which became zero in Italian.