In the mid-1780s, anatomist Luigi Galvani (Bologna, Italy) was studying the effects of atmospheric electrical discharge. One day, in his garden, he fastened brass hooks between the spinal cord of a dissected frog and an iron railing. To his amazement the frog's legs began twitching wildly, not only when lightning flashed, but also when the sky was calm. Galvani interpreted his results in terms of animal electricity (incorrect). Galvani proclaimed that the muscle retained a nerveo-electrical fluid similar to that of an electric eel. While his papers on the subject ignited research among scientists of Europe, the most significant consequence of Galvani's discovery was the concept of Galvanism which refers to the production of electrical current from the contact of two metals in a moist environment. Shortly before he died, Galvani was dismissed from his professorship at the University of Bologna, because he refused to swear allegiance to Napoleon's Republic.
Alessandro Giuseppe Volta (1745-1827)
Volta was born in Como, Italy (near Milan). In 1774, he began his first academic position as principal of the state Gymnasium in Como. In 1777, he was appointed Professor of Physics at the University of Pavia. Here he began to repeat Galvani's famous experiments with decapitated frogs. He observed that Galvani had connected brass hooks between the frog's spinal cord and an iron railing. According to Volta's interpretation, the muscle twitches were induced by current flowing between two dissimilar metals connected by the moist flesh of the frog's leg. This led him to develop the first device which demonstrated chemical production of electric current. In 1799, Volta arranged a vertical pile of metal discs (zinc with copper or silver) and separated them from each other with paperboard discs that had been soaked in saline solution. This stack became known as the voltaic pile and was the first electric battery.
In his pursuit of the current generated by his primitive batteries, Volta developed several new devices. He invented the electrophore, a forerunner of the capacitor; the condensatore, a device that detected weak electrical current; and the straw electrometer, a meteorology tool which measured atmospheric electricity. The term volt, a unit of electrical measurement, is named in his honor. In 1801, Volta was summoned to Paris to demonstrate his discovery before the Academy of Sciences. Napoleon declared his presentation a triumph, awarded him a gold medal and initiated the annual Volta Prize in his honor.
Humphry Davy (1778-1829)
At 19, Davy began studying chemistry after reading papers by Antoine Lavoisier. Within five years he was appointed Professor of Chemistry at The Royal Institution in London. In his first scientific work, Davy investigated the possible therapeutic value of inhaling various gases, using himself as a guinea pig. Since nitric oxide (laughing gas) and carbon monoxide were among the gases studied, it is surprising he survived. Davy utilizes the recently discovered voltaic pile to lay the qualitative foundations of electrochemistry. Davy isolated elemental potassium which was soon followed by sodium, barium, calcium, strontium, and magnesium. Davy later isolated boron and silicon.
Late in 1813, Davy set out on an 18 month tour of Europe accompanied by young Michael Faraday. Though neither then realized it, Davy's star was beginning to set while Faraday's was soon to rise. Faraday was to succeed Davy at The Royal Institution. Some have unkindly suggested that Davy's greatest discovery was Michael Faraday. Strictly as a chemist, Davy was the greater of the two. As a scientist, Faraday was incomparable.
Michael Faraday (1791-1867)
Although Faraday came from very humble beginnings, left school at the age of 12, and was essentially self-taught, he is acknowledged as one of the greatest of all scientists.Davy was Faraday's mentor in his early years of physics and electrochemistry research. For a time, in fact, Faraday extended and developed the research begun by Davy at the Royal Institution in London, where Faraday began his career in 1813 as Davy's Laboratory Assistant. Most of Faraday's early experiments and published papers bore the stamp of Davy's involvement.
Faraday achieved scientific prominence of his own for the First Law of Electrochemistry, developed in 1834: The chemical power of a current of electricity is in direct proportion to the absolute quantity of electricity which passes. The Second Law of Electrochemistry, also defined by Faraday, states: Electrochemical equivalents coincide, and are the same, with ordinary chemical equivalents. The work that led to these two laws also resulted in many of the modern electrochemical terms such as electrode, electrolyte, and ion.
But Faraday didn't consider himself an electrochemist; he preferred the title of natural philosopher and devoted his life to proving the interconnection of natural forces. His electrochemical research was one outcome of this effort, exploring the connection between the chemical and electrical forces of the voltaic battery.
Johann Wilhelm Ritter (1776-1810)
Ritter was born in Poland and began his career as an apothecary. He went to the University of Jena in 1796 to study science. Ritter made the first dry cell battery in 1802 and storage battery in 1803; While working with silver chloride, Ritter discovered the ultraviolet end of the spectrum. Ritter's most important contribution came in 1798 when he established an explicit connection between galvanism and chemical reactivity. He correlated the electrical effects produced by various metal couples on the muscle with differences in the metals' ease of oxidation. His suggestion that current was due to a chemical interaction between the metals was the first electrochemical explanation of this phenomenon. Fascinated by experiments in electrical excitation of muscle, Ritter performed experiments on his own body with very high voltages. Undoubtedly, these experiments led to his untimely death at the age of 33.
John Frederic Daniell (1790-1845)
Daniell was born in London and was appointed professor of chemistry at King's College, London. Daniell's research into development of constant current cells took place at the same time (late 1830s) that commercial telegraph systems began to appear. Early telegraph messages were brief and traveled short distances. Daniell's copper battery (1836) became the standard for British and American telegraph systems. In 1839, Daniell experimented on the fusion of metals with a 70-cell battery. He produced an electric arc so rich in ultraviolet rays that it resulted in an instant, artificial sunburn. These experiments caused serious injury to Daniell's eyes as well as the eyes of spectators. Ultimately, Daniell showed that the ion of the metal, rather than its oxide, carries an electric charge when a metal-salt solution is electrolyzed.
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