In this exploration of magnesium history, the focus will be on the men involved. These men were not well educated in terms of today's educational requirements. Most were self-educated in the development of the technologies and their strong beliefs were honed by constant thought and practice. Their reward was primarily scientific progress and not necessarily material reward.
Discovery of Magnesium Compounds
In 1701, M. B. Valentine prepared heavy magnesium carbonate from mother liquors obtained in the manufacture of potassium nitrate. Magnesia was confused with lime until 1754 when J. Black showed that the two substances were entirely different. Deposits of natural magnesium carbonate were discovered in Moravia in 1803 and were described by C. F. Ludwig as 'talcum carbonatum'. The term 'magnesite' was first restricted to the natural carbonate in 1808 by Dr. L. G. Karsten and was generally accepted gradually although the term 'globertite' was used in France for some time thereafter.
Sir Humphrey Davy (December 17, 1778 – May 29, 1829)
Sir Humphrey Davy is credited with the discovery of magnesium in 1808. Davy was an English chemist who was the first person to apply electrical current to isolate the alkali metals. He was born in Penzance, Cornwall, the son of a woodcarver. He was not a good student, his interest in the outdoor life being too commanding. His love of fishing continued until the end of his life. He first became interested in science in 1797 when he read some writings of Lavoisier and Nicholson.
After receiving a grammar school education, he was apprenticed to a surgeon and began medical studies, turning to chemistry in 1797 after experimentation in the offices of the physician with whom he was studying. The experiments came to the attention of Davies Gilbert, president of the Royal Society. Under Gilbert's sponsorship, in 1798, at the age of 20, Davy was appointed Superintendent of the Medical Pneumatic Institution, established in Bristol by Dr. Thomas Beddoes to study the physiological effects of new gases. In 1799, Beddoes published two papers on the work that Davy was doing. In spite of the fact that the conclusions in the first two papers were refuted, much publicity came to the Institution and to Davy. Later that year, Davy discovered and reported on the anesthetic properties of nitrous oxide (laughing gas). He suggested that it could be used in dental practice. It took nearly 50 years before the gas was tried in anesthesia.
In 1801 Davy was appointed to the newly established Royal Institution as an assistant lecturer under Count Rumford, and in 1802 advanced to professor. As a lecturer, Davy achieved a performance and presentation that could be envied by modern-day stage performers, much less college professors. History tells us that his chemical lessons and demonstrations were brilliantly presented. It was through these lectures that he first met Michael Faraday. Davy also wrote a book on agricultural chemistry and, presently, the first systematic geology course to be offered in England. His first Bakerian lecture on his experimentation on Galvinism in 1802 won the Medal of the French Institute from Napoleon, even though France and England were at war at that time.
Davy started experiments to produce metallic materials from a number of alkaline earth materials. During this work, it has been said that he laid the foundations for the world's lightest metal industry within the space of little more than a year. In 1807, he treated clay with sulfuric acid and found that reaction produced an unknown metal. He called it aluminum. He was unable to separate the new metal from oxygen in the air so he called the compound alumina. Davy started investigating the use of electricity by using a number of electrical cells in series to create a high-power battery. He passed current from the battery through water and found that he could dissociate water into hydrogen and oxygen. When he tried the same technique with a solution of potash, he still got hydrogen and oxygen. When he substituted solid potash, moistened to conduct current, he obtained fusion and isolated potassium for the first time. He quickly followed this by repeating the process and isolating sodium. After many unsuccessful attempts to use his developed procedure to isolate other alkaline metals, he altered his experimentation and followed a suggestion contained in a letter from Berzelius and Pontin. Davy succeeded in producing an amalgam of calcium, barium, strontium, and magnesium, and isolating the metals by driving off the mercury. As in the case of the alkali metals, he named the alkaline-earth metals after their oxides baryta, strontia, chalk, and magnesia, calling them Barium, Strontium, Calcium, and Magnium (at the time the word 'magnesium' was used to denote manganese).
Davy's technique consisted in mixing moistened alkaline-earth-oxide with cinnabar (mercuric sulfide) and placing the resultant paste on a platinum plate. A hollow was made in the paste to receive a drop of mercury, the whole was covered with naphtha and the platinum plate and the drop of mercury connected to the poles of the voltaic pile. The amalgam, which formed on the mercury pole, was transferred to a glass tube and the mercury distilled off. Davy gave the following description of the characteristics of magnesium:
"The metal from magnesia appears to react with the glass, especially before all the mercury has distilled off. In one experiment, in which I interrupted the distillation before the mercury had been completely removed, the metal appeared as a solid body, which exhibited the same white color and the same luster as the other metals of the alkalide-earths. It immediately sank to the bottom of the water although surrounded by gas bubbles, formed magnesia. It changed quickly in the atmosphere, a white crust forming, and finally it disintegrated into a white powder, which proved to be magnesia."
Davy later showed that oxygen could not be removed from the substance known as oxymuriatic acid and proved this substance to be an element, which he called chlorine. Davy became ill and resigned from the Royal Institution in 1812. One wonders about his veracity of his illness when we find he delivered a farewell lecture, married a wealthy widow, was knighted, and then traveled on the continent for two years taking with him his wife and assistant, Michael Faraday. Davy was known to have remarked more than once that the greatest discovery he ever made was Michael Faraday.
Michael Faraday (September 22, 1791 – August 25, 1867)
Faraday was the son of a blacksmith that was apprenticed as a bookbinder. He had a voracious appetite for the printed word, reading all the books that were brought in for binding. He was especially stimulated and challenged by technical manuscripts. After completing his apprenticeship, Faraday became a journeyman bookbinder and worked in this trade until 1813. He impressed Davy and was appointed assistant in the laboratory of the Royal Institution of Great Britain. Faraday and Davy traveled extensively in Europe during 1813-1815. It was during this period that he may have met Bunsen.
The milestones set by Faraday are monumental in the history of chemistry. At one point in time under the tutelage of Davy Faraday was a major mover in the development of the user of electricity and chemistry of the science of electrochemistry. The Laws of Electrochemistry are called Faraday's Laws. It is the law that establishes that 1000 Amperes of current passing for one hour will release one pound of magnesium. [Note: the actual law says that the amount of electricity that must be passed through an electrolyte in order to deposit (at the anode or cathode) or dissolve (from the anode) 1 gram equivalent of any substance is 96,500 ampere-seconds or coulombs: the quantity of electricity is called a faraday.]
Magnesium was first isolated in 1828 by the French chemist, H. Bussy. Actually, Bussy developed a method for producing dehydrated magnesium chloride by adding chlorine to an intimate mixture of starch and magnesium oxide at elevated temperatures. The principle is the same as in use today although the starch is replaced by active carbon or carbon monoxide. Bussy is not remembered for his chloride process, but for adding potassium to the melt and thus directly the first metallic magnesium in a metallothermic process.
Faraday produced magnesium in 1833 by electrolysis of fused anhydrous magnesium chloride.
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