MICHAEL FARADAY 1791 - 1867

(G3b, G3c, G4, W4, Va, Vb)

Acknowledgements

Faraday: by the English portrait photographer John Watkins (1823-1874),1860s – National Portrait Gallery, London. Lecture: lithograph by the Scottish artist Alexander Blaikley (1816-1903), 1856, contained in Notes and Records of the Royal Society of London, 2002, Volume 56. Tyndall: 1873, artist unknown – Dibner Collection, Smithsonian Institution Libraries, Washington. Whewell: artist unknown, frontispiece of The Life and Selections from the Correspondence of William Whewell by Mrs Stair Douglas, 1991, facsimile reprint of an 1881 edition – private collection. Henry: engraving, artist unknown, from a frontispiece to A Memorial of Joseph Henry, published by order of Congress in 1880 – Royal Institution, London. Graham: date and artist unknown. Wohler: artist unknown, contained in The Popular Science Monthly, Volume 17, 1880. Liebig: by Scottish painter Alexander Craig (1808-1878), c1856, after a chalk drawing by the English artist Samuel Lawrence (1817-1884) – Science Museum, London.

xxxxxThe English chemist and physicist Michael Faraday, by his pioneering experiments in electromagnetism, made the first primitive but practical models of the electric motor and dynamo. By so doing he laid the foundations of modern electrical engineering. He also introduced lines of magnetic force, investigated the effect of magnetism on light, and, by his contribution to chemistry - notably the discovery of the basic laws of electrolysis - has come to be regarded as the father of electrochemistry.

xxxxxFaraday was born in Newington, Surrey, the son of a blacksmith. He had very little formal education, and at the age of fourteen began work as an apprentice to a London bookseller and binder. Over the next seven years he read widely, and became particularly interested in the current books and articles on science. He began experimenting with electricity in his spare time, and at the age of twenty he attended a number of lectures given by Humphry Davy. Afterwards, he sent the notes he had made to this eminent English scientist, and these clearly made an impression. In 1812 he was appointed Davy’s secretary and, later, his laboratory assistant at the Royal Institution. Such was his contribution to the scientific work being carried out there, that he was elected to the Royal Society in 1824, and became the director of the Institution’s laboratory the following year. Then in 1833 when Davy retired, he succeeded him as professor of chemistry. For much of his career, from 1825 to 1862 in fact, he gained a reputation for the popular lectures he gave at the Institution. These included his “Friday evening discourses”, attended on one occasion by Prince Albert and two of his sons. He died at his home near Hampton Court in Surrey, and was buried in Highgate Cemetery in north London.

xxxxxIt is in the field of physics that Faraday’s work is best remembered and valued. As we have seen, it was in April 1820 (G4) that the Danish physicist and chemist Hans Christian Oersted discovered that electric current in a wire was able to deflect a magnetic needle. Soon afterwards the French physicist and mathematician André Ampère elaborated on this finding, and demonstrated that magnetic force was a circular force, producing in effect a cylinder of magnetism around the wire. Faraday was the first to realise that this force could be put to work. He reasoned that if a magnetic pole could be isolated, then it would move constantly in a circle around a current-bearing wire, producing his so-called “electromagnetic rotation”. In 1821 he constructed a piece of apparatus which, though primitive in design, clearly demonstrated the basic principles which govern the electric motor. He had succeeded in transforming electrical energy into mechanical energy, thereby producing a source of power.

xxxxxOver the next ten years his research led him to the conclusion that, since an electric current could cause a magnetic field, a magnetic field should be able to produce an electric current. In 1831 he carried out a series of experiments which demonstrated this principle of electromagnetic induction, (the converse of Oersted’s finding), and explained the laws which governed it. The device he then built to reach this conclusion proved to be the first successful attempt at the construction of an electric dynamo, the forerunner of the modern generator. The following year he illustrated the lines of electric and magnetic force by the use of iron filings. This was seen as unnecessary by most scientists at that time, but later, as we shall see, the Scottish physicist James Clerk Maxwell accepted this concept and put Faraday’s ideas into mathematical form.

 

xxxxxFaraday’s advances in chemistry were just as impressive. In this field his greatest contribution was in electrolysis. This method of decomposing or splitting up a chemical compound by passing an electrical current through it had been pioneered by Davy, but Faraday made much greater use of this phenomenon, and in 1834 arrived at its two fundamental laws. Earlier, in the 1820s, he discovered two new chlorides of carbon, and was the first to liquefy chlorine, later using this coolant to liquefy a number of common gases. And during this period - among other advances - he isolated benzene from gas oils (a substance used as a basis for permanent dyes), produced the first stainless steel, and extracted aluminium from other ores. In 1831 he spent some time working with Charles Wheatstone on the theory of sound. Later in his career, he turned his attention to the nature of light, and established what is known as the “Faraday effect”, based on his discovery, made in 1845, that an intense magnetic field has the power to rotate the plane of polarized light.

xxxxxFaraday, a man of extraordinary ability over a wide range of subjects, astonished the scientific world by his findings, particularly those achieved in physics. Like Davy, he received a number of high honours, including the Royal and Rumford medals of the Royal Society. However, an extremely modest man, he declined the presidency of the society and rejected a knighthood, wishing to remain plain Mr. Faraday. Towards the end of his life he was awarded a pension, and accepted the use of a cottage near Hampton Court. The importance of his contribution to scientific knowledge was immense. It was largely upon the foundation laid down by his painstaking experimental research that the Scottish physicist James Clerk Maxwell was able to build his concept of the electromagnetic field, paving the way for Albert Einstein’s theory of relativity. Apart from papers and articles, Faraday’s major works were Chemical Manipulation of 1827, Experimental Researches in Electricity, three volumes produced from 1844 to 1855, and Experimental Researches in Chemistry and Physics, published in 1859.

xxxxxIncidentally, between the years 1827 and 1860 Faraday gave nineteen “Christmas Lectures” at the Royal Institution, each “adapted to a juvenile audience”. These lectures for young people are still held every year, and they are named after him. One of the last lectures he gave in this series was entitled The Chemical History of a Candle, and this was the name he gave to the book he published in 1860. Containing six of his children’s lectures, it has become a classic of science literature. ……

xxxxx…… A deeply religious man, when the Crimean War broke out in 1853 he was asked to take charge of a project to produce poison gas for use on the battlefield, but he refused to do so. Likewise, when Queen Victoria invited him to lunch on a Sunday, he eventually accepted, but later sought forgiveness from the Church authorities for not attending a service on that day. ……

 

xxxxx…… Not until he gained universal fame did Faraday overcome his humble origins. When he went on a grand tour of Europe with Davy in 1813, acting as his secretary, Davy’s wife made him sit and eat with the servants.

xxxxxAmong Faraday’s close friends was the prominent Irish physicist John Tyndall (1820-1893). He studied under Robert Bunsen at the University of Marburg, and then carried out extensive research into diamagnetism, radiant heat, atmospheric gases, and the science of climate change. He was a friend of the English scientists T.H. Huxley and Herbert Spencer, and in the 1850s, as professor of physics, he succeeded Faraday in giving popular science lectures at the Royal Institution in London. He wrote a large number of popular books and articles on experimental physics, produced a biography of Faraday, and in his leisure time was an experienced mountaineer. He was elected a fellow of the Royal Society in 1852, and during his research he gave the first scientific explanation as to why the sky is blue!

 

xxxxxIncidentally, in 1872-73 Tyndall made a highly successful lecture tour of the United States. He earned a great deal of money, but he donated it all to the advancement of American science.

xxxxxThe English physicist and philosopher William Whewell (1794-1866) (illustrated) was one of a number of scientists at this time who were researching into electromagnetism. He produced two scholarly works on the subject, The History of the Inductive Sciences of 1837 and The Philosophy of the Inductive Sciences three years later. Whewell studied at Trinity College, Cambridge, and lectured there throughout his life. He became master of the college in 1841, and vice chancellor of the university the following year. He is said to have coined a number of scientific terms, including scientist, electrode, cathode and anode, but it was Faraday who made them popular. Andxin 1825 the English electrical engineer William Sturgeon (1783-1850) invented the multi-turn electromagnet, capable of lifting twenty times its weight.

xxxxxAnd scientists were also at work abroad. As we have seen, the French mathematician and physicist Siméon-Denis Poisson, a close friend of the mathematicians Pierre-Simon de Laplace and Joseph-Louis Lagrange, made a valuable contribution to physics by applying mathematics to current findings, particularly with regard to electricity, magnetism and mechanics.

xxxxxMeanwhile in the United States it became evident that the brilliant physicist Joseph Henry (1797-1878) observed the phenomenon of electro-magnetic induction in 1830, some months before Faraday published his findings and was given credit for the discovery. Henry went on to create an electromagnet for Yale College which was able to lift more than a ton of iron - a marked improvement on Sturgeon’s version - and he also developed a electromagnetic relay system in 1835. This assisted him in the design and construction of a telegraph which proved successful over more than a mile. He let the American inventor Samuel Morse and the English inventor Charles Wheatstone know about his relay system - both of whom failed to acknowledge his assistance, - and he was one of Abraham Lincoln’s technical advisors during the American Civil War. In recognition of his achievements in the field of electro-magnetism, in 1893 the electrical unit of inductive resistance, the henry, was named after him.

xxxxxIncidentally, when Henry became the first secretary of the Smithsonian Institution in Washington D.C. in 1846, he began organizing a voluntary network of stations equipped with meteorological instruments. These telegraphed weather reports to the Institution, and these weather conditions were then published. By 1860 about 500 stations were sending in reports, and this led to the founding of the US Weather Bureau in 1870.

xxxxxIt was around this time (1833) that the Scottish chemist Thomas Graham (1805-1869) published his findings on the diffusion of gases. The law he then established (Graham’s Law) states that the diffusion rate of a gas is inversely proportional to the square root of its molecular weight. He was one of the earliest scientists to make a study of colloids - solutions in which the dispersed particles are much larger than atoms or molecules but still invisible to the naked eye - and is regarded as the founder of this branch of chemistry. During his research he determined the distinction between colloids (such as glue and starch), and crystalloids (such as common salt), and he was the first to discover the method of dialysis (osmosis) by which colloids could be separated from true solutions. In 1833 he made a study of the three forms of phosphoric acid (ortho, pyro and meta), and this work led to the concept of polybasic acids. He was the first to use the terms gel, colloid and dialyzer, the precursor of today’s dialysis machine.

xxxxxGraham was born in Glasgow, the son of a textile manufacturer. He studied in his home town and then at Edinburgh, and spent the years 1837-54 lecturing at University College, London. In 1855 he was appointed master of the Royal Mint. Unlike Faraday, he was not particularly successful as a lecturer, but he excelled in practical laboratory work.

xxxxxAnd it was in this period, in 1827 in fact, that the German chemist Friedrich Wohler (1800-1882) developed a method that isolated the metals beryllium, titanium and aluminium from their ores. Then a year later he became the first scientist to synthesize an organic compound from an inorganic compound (urea from ammonium cyanate). This achievement put an end to an earlier misconception on this subject, and marked the beginnings of organic chemistry. He later isolated silicon and boron, and discovered quinone, quinol and calcium carbide.

xxxxxWohler was born near Frankfurt-am-Mein. He went to Heidelberg to study medicine, but whilst there became interested in chemistry, and went to Stockholm to study under the Swedish chemist Jöns Berzelius. He became professor of chemistry at the University of Gottingen in 1836. He was an outstanding teacher, and produced a number of textbooks on organic and inorganic chemistry.

xxxxxIt was while making a study of cyanates that Wohler struck up a close friendship and productive partnership with his compatriot, the German chemist Justus von Liebig (1803-1873). Starting in the early 1830s, they worked together over a number of years and investigated, among other substances, benzaldehyde and uric acid and its derivatives. They edited the journal Annals of Pharmacy for over forty years and this carried useful reports on new developments in chemistry. Liebig discovered chloroform and chloral and, by his study of plants, soil fertility and artificial manures, made a major contribution to agricultural chemistry. In addition he was interested in the calorific value of certain foods, divided foods into fats, carbohydrates and proteins, and even developed and marketed his own beef extract!

xxxxxLiebig was born in Darmstadt, Hesse, and studied at Bonn, Erlangen and Paris. He was appointed professor of chemistry at the University of Giessen at the age of 23 and over the next twenty five years made his research laboratory internationally famous, both for the quality of its work in physiological chemistry, and for the string of able scientists it produced. He was appointed to the chair of chemistry at Munich University in 1852. He founded the journal Annals of Pharmacy in 1832, and published his Animal Chemistry ten years later. He was made a baron in 1845.

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