1.2 LANDMARKS IN THE HISTORY OF CHEMISTRY
Over the centuries, chemistry has undergone remarkable progress. Chemistry from the very beginning was, however, used in a number of arts and crafts, such as pottery making, glass making, dyeing and in metallurgy. All these developments were empirical (experimental) that is they were achieved by trial and error and not on the basis of any systematic study.
1.2 (a) THE GREEK PERIOD
Greek philosophers like Plato (347 - 428 B.C), Aristotle (322-384 B.C), Democritus (357-460B.C) and many others contributed a lot in number of small way to the early development of chemistry. They introduced the concept of elements, atoms and the chemical reactions. They thought that all matter was derived from four elements, earth, air, fire and water. These elements have properties of their own such as hot, dry, cold and wet. According to them, fire was hot and dry, earth was dry and cold, water was cold, hot and wet and air was cold, wet and hot.
The Romans developed the chemical arts still further. They improved metallurgical processes and introduced the enameling of pottery. However, they developed little theoretical knowledge in this regard. Their works were all empirical.
(b) THE MUSLIM PERIOD
The Muslim period was from 600 to 1600 A.D in the history of chemistry and is known as the period of alchemists. In the middle ages, chemistry was given a spurt of work. During the first few centuries of Hijra, the Muslim scientists made rich contributions to the various branches of science, especially in the field of chemistry and introduced scientific methods and experimentations. The modern scientific knowledge is based on the contributions of these Muslim scholars.
The alchemists developed and used many laboratory equipments such as funnels, beakers, crucibles for melting and fusion, retorts for distillation, balances for weighing, etc. They discovered various acids, alcohols and medicines.
Jabir Ibne-Haiyan (721 - 803 A.D), generally known as the father of alchemy, invented experimental methods for the preparations of nitric acid, hydrochloric acid and white lead. He also developed methods for the extraction of metals from their ores and dyeing cloths.
Al-Razi (862 - 930 A.D) was a physician, alchemist and a philosopher. He was an expert surgeon and was the first to use opium as an anesthesia. He divided the substances into living and non-living origins, which was later adopted by Berzellius, in 1806 to classify chemical compounds on the basis of their origins as organic and inorganic compounds. Al - Razi prepared ethyl alcohol by the fermentation process.
Al - Beruni (973 - 1048 A.D) contributed a lot in physics, metaphysics, mathematics, geography and history. In the field of chemistry, he determined the densities of different substances.
Ibne-Sina (980 - 1037 A.D) was famous for his contribution in the field of medicines, medicinal chemistry, philosophy, mathematics and astronomy.
These Muslims alchemists were interested more in finding a way to prolong life and to convert baser metals like lead, copper into gold. Although their efforts were futile but their researches led to the discoveries of many substances and laid the foundation of chemistry. By the late sixteenth century, a lot of chemical laboratories sprang up and the important reagents like sulphuric acid, nitric acid, hydrochloric acid, silver nitrate, etc were discovered. Chemists of that period, however, devoted their energies mainly to the production of drugs for the use of medicines.
(c) THE MODERN PERIOD
Robert Boyle (1627 - 1691 A.D) described affectionately as the father of modern chemistry, was .the first to put forward the idea that chemistry should be regarded as a systematic investigation of nature with the sole aim of promoting knowledge. As a result, lots of discoveries were made during later years.
J. Black (1728 - 1799) made a study of carbon dioxide.
J. Prieslly (1733 - 1804) discovered oxygen, sulphur dioxide and hydrogen chloride.
Scheele (1742 - 1786) discovered chlorine. Cavendish (1731-1810) discovered hydrogen, Lavoisior (1743 - 1794) discovered that oxygen constituted about one-fifth of air. John Dalton (1766 - 1844) made a great stride in chemistry with his atomic theory of matter. The idea of atoms and molecules became the established fact and the concept of atomic weight was also given by John Dalton.
Gay - Lussac (1778 - 1850), Avogadro (1776 - 1856), Dulang (1785 -1838) and Petit (1741 - 1820) and others led to the determination of relative atomic and molecular masses of many substances. Meanwhile J.J. BerzeUius (1779 - 1848) introduced the idea of symbols, formulae and chemical equation to make the study more systematic. This was further enhanced by Mendeleeff (1824 - 1907) who discovered the periodic arrangement of the elements. The ionic theory and the laws of electrolysis were put forward by Arrhenius (1859 - 1927) and M. Faraday (1791 - 1867), respectively. The works of J.J. Thomson (1856 - 1940), H. Becquerel (1852 - 1908), M. Curie (1867 - 1934), Neil Bohr (1885 - 1962) and E. Rutherford (1891 -1937) led to the discoveries of structure of atom, radioactivity, there by opening the door of the present nuclear age.