Davy Develops the Arc Lamp Summary

  • Last updated on November 10, 2022

Through his experiments with the newly discovered voltaic battery, Humphry Davy created a brilliant light by bringing two carbon electrodes near each other. He continued to refine the design and later dramatically demonstrated his invention with increasingly powerful batteries.

Summary of Event

From the start of his scientific career, Sir Humphry Davy was fascinated by light. His interest developed from reading Antoine-Laurent Lavoisier’s Traité élémentaire de chimie (1789; Elements of Chemistry, 1790) in Robert Kerr’s 1790 English translation. This pivotal work of the chemical revolution contained the first table of elements, and “light” was at the top of Lavoisier’s list of “simple substances,” followed by “caloric,” the heat substance that played a fundamental role in his analysis of the three states of matter (solid, liquid, and gas). Arc lamp Davy, Sir Humphry Electricity;and lighting[Lighting] Lighting;electric Batteries, electrical [kw]Davy Develops the Arc Lamp (c. 1801-1810) [kw]Develops the Arc Lamp, Davy (c. 1801-1810) [kw]Arc Lamp, Davy Develops the (c. 1801-1810) [kw]Arc Lamp, Davy Develops the (c. 1801-1810) [kw]Lamp, Davy Develops the Arc (c. 1801-1810) Arc lamp Davy, Sir Humphry Electricity;and lighting[Lighting] Lighting;electric Batteries, electrical [g]Great Britain;c. 1801-1810: Davy Develops the Arc Lamp[0050] [c]Inventions;c. 1801-1810: Davy Develops the Arc Lamp[0050] [c]Science and technology;c. 1801-1810: Davy Develops the Arc Lamp[0050] [c]Engineering;c. 1801-1810: Davy Develops the Arc Lamp[0050] Volta, Alessandro Lavoisier, Antoine-Laurent

Influenced by Sir Isaac Newton’s Newton, Sir Isaac ideas, Davy was critical of Lavoisier, Lavoisier, Antoine-Laurent stating that light was “corpuscularian,” not elemental, and that heat was not a substance but a result of the motions of material particles. He also disagreed with Lavoisier’s speculations that caloric (or heat) was a modification of light. One of Davy’s early investigations involved firing a gunlock in a vacuum and in carbon dioxide. Since he saw no sparks at the moment of ignition, Davy concluded that light is not caloric but a kind of matter. When he repeated the experiment in oxygen, he saw brilliant sparks. This led him to propose that Lavoisier’s “oxygen” was really a composite of light and oxygen, which he named “phosoxygen,” a view that he later repudiated. In 1799, Davy’s “An Essay on Heat, Light, and the Combinations of Light” was published in Thomas Beddoes’s collection, Contributions to Physical and Medical Knowledge: Principally from the West of England (1799).

Although Lavoisier’s treatise helped stimulate Davy’s investigations of heat and light, the instigating event in his electrochemical studies and his invention of the arc lamp was Alessandro Volta’s invention in 1800 of the electric battery (or “voltaic pile”), a device that produced a steady flow of electrical current. Volta soon communicated his discovery to the Royal Society of London, and Davy was so impressed by Volta’s invention that he saw it as an “alarm-bell” for himself and other experimenters. When William Nicholson and Anthony Carlisle used a voltaic pile to decompose water into its component gases, hydrogen and oxygen, Davy became fascinated by the connection between electrical and chemical forces. He disagreed with Volta’s interpretation that the electrical force was generated by contacts between dissimilar metals in the battery, arguing, instead, that a chemical reaction produced the current.

Davy began using the electric battery for various projects, but precisely when he used a voltaic pile to generate light between two charcoal rods is not clear. Most scholars suggest dates between 1800 and 1810. Pinpointing the time is complicated by events in Davy’s life, as well as by his habit of revising and expanding his early work in response to later scientific observations and experiments. Davy was between positions when some of his early research was done. He had been doing important medical research on nitrous oxide at Beddoes’s institute in Bristol, but, at the invitation of Benjamin Thompson, Count von Rumford, he moved to the Royal Institution Royal Institution in London early in 1801.

Some of Davy’s experiments on “galvanic electricity” were published while he was in Bristol, including his discovery that charcoal worked as effectively as metals in producing sparks when connected to a voltaic pile. Around that time, Davy was also performing experiments that showed that silver salts were blackened by light, a process that would be central to the invention of photography Photography;invention of by Nicéphore Niépce in 1826. He also showed that electric current from a voltaic pile could produce light when it heated thin wires of platinum or other metals to incandescence.

Some scholars assert that, before Davy moved to London, he had already noticed the light produced between two carbon rods when they were connected to a voltaic pile. Because the resulting discharge traced an arc between the rods, this device became known as an arc lamp, or arc light, and Davy has been given credit as the first person to create such a lamp. This arc of electricity, which had high current and low voltage, was both brilliantly luminous and intensely hot. No commercial applications emerged from Davy’s early research, but he did use the heat of the arc in several experiments.

Most of Davy’s greatest work in electrochemistry Chemistry;electrochemistry took place at the Royal Institution Royal Institution;and electrochemistry[Electrochemistry] of Great Britain during the first decade of the nineteenth century, when he proved himself as an outstanding lecturer, excellent fund-raiser, and innovative researcher. He published his observations about the arc light in the Royal Institution’s journal in the summer of 1802. However, because of the institution’s emphasis on practical research, for the next few years Davy devoted himself to applied chemistry rather than continuing his work in electrochemistry. Between 1806 and 1810, with an interruption due to illness, Davy made the discoveries for which he became best known, including further work on electrical illumination based on his access to vastly improved batteries.

During these years of productivity, the batteries that Davy used went from utilizing 250 metallic plates to utilizing 500 plates and eventually 2,000 plates—some of the most powerful batteries ever built. With such powerful sources of electricity, Davy was able to isolate, in 1807, potassium from molten potash (potassium carbonate) and sodium from molten soda (sodium carbonate). In 1808, he used electricity to separate several metals from their oxides, including magnesium, strontium, barium, and calcium. In this way, Davy proved that several substances that Lavoisier Lavoisier, Antoine-Laurent had listed as elemental, such as magnesia, were really compounds. With his battery of 2,000 plates, Davy demonstrated that muriatic acid (hydrochloric acid) contained no oxygen, contrary to Lavoisier’s assertions, and that Lavoisier’s “oxymuriatic radical” was really elemental chlorine.

In 1809, Davy used a bank of powerful batteries to stage a demonstration of the arc lamp. Before an audience at the Royal Institution, a brilliant, arc-shaped light was generated between two carbon rods that were a few inches apart. Some scholars call this demonstration “the birth of the arc lamp.” Accounts of this demonstration are more numerous and detailed than the evidence for Davy’s 1801 arc-light experiments. Witnesses in 1809 spoke of a light so intense that it rivaled the Sun’s. Furthermore, the light was not confined to the area between the electrodes but spread into the air beyond the gap. However, because of the intense heat, the tips of the carbon rods were consumed, and, to maintain the light, the rods had to be carefully pushed closer together.

Some scholars state that this demonstration at the Royal Institution occurred in 1808, while others claim that Davy’s carbon electric arc lamp was first exhibited in 1810. Perhaps this confusion is due to repetitions of the dramatic experiment before different audiences. A witness to the 1810 demonstration reported that the “arch of light” was so intense that any substance introduced into it “instantly became ignited,” including quartz, sapphire, and magnesia. Although Davy went on to invent the miner’s Mining;safety lamps safety lamp in 1815, he did not foresee any practical applications for his arc lamp. After his knighthood and marriage in 1812, his interests moved away from electrochemistry.

Significance

It took several decades before the practical significance of Davy’s arc lamp was realized. In order to have arc lighting available for extended use, a feed mechanism that kept the carbon electrodes at the proper distance was needed, since the rods became shorter because of combustion. After such a mechanism was developed in the 1840’s, arc lamps made their appearance on the streets of Paris and in its opera Opera;lighting house. Commercial applications of the electric arc multiplied in the 1850’s. For example, an arc lamp was installed in the South Foreland Lighthouse in the English Channel, and an arc light was turned on in the Clock Tower of London’s Palace of Westminster whenever Parliament was in session.

With the increased availability of powerful dynamos and with the invention of an improved form of the arc lamp known as the Jablochkov candle, whose light was less harsh than that of earlier arc lamps, cities in Europe and the United States began to light their streets and public buildings with the new devices. Gas lighting Lighting;gas was still the largest illuminating industry, but arc-lamp systems developed by Charles F. Brush and others led to the lighting of streets in Cleveland, New York, and Washington. Arc lighting was also part of the American Centennial World’s Fair in Philadelphia World fairs;Philadelphia Philadelphia;World’s Fair (1876) and the Chicago World’s Columbian Exposition (1893). However, arc lights were too harsh and bright for homes and offices. Only after Thomas Alva Edison developed the first truly practicable incandescent lamp in 1879, along with a system to distribute direct-current electricity, did the electric light, which had begun so modestly in the experimental work of Davy, spread throughout the world.

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Bowers, Brian. A History of Electric Light and Power. New York: Peter Peregrinus, 1982. This volume, part of a history of technology series, centers on how electricity was brought to the public. The early chapters deal with Davy and Michael Faraday. References at the ends of chapters. Index.
  • citation-type="booksimple"

    xlink:type="simple">Fullmer, June Z. Young Humphry Davy: The Making of an Experimental Chemist. Philadelphia: American Philosophical Society, 2000. This book, which covers Davy’s career until the start of his tenure at the Royal Institution, contains material on his early work in electricity and light. Notes to primary and secondary sources at the ends of chapters, a select bibliography, and an index.
  • citation-type="booksimple"

    xlink:type="simple">Golinski, Jan. Science as Public Culture: Chemistry and Enlightenment in Britain, 1760-1820. Cambridge, England: Cambridge University Press, 1992. Chapter 7, “Humphry Davy: The Public Face of Genius,” is an examination of Davy’s electrochemical research with an emphasis on its practical applications and its social setting. Extensive bibliography and index.
  • citation-type="booksimple"

    xlink:type="simple">Hartley, Harold. Sir Humphry Davy. Reprint. London: EP, 1973. The standard account of Davy’s life. Bibliography and index.
  • citation-type="booksimple"

    xlink:type="simple">Knight, David. Humphry Davy: Science and Power. 2d ed. Cambridge, England: Cambridge University Press, 1998. Based on Davy’s notebooks, his formal and informal writings, and his poetry. Introduces general readers to what Knight calls “the first professional scientist.” References to primary and secondary sources in the notes to the chapters, select bibliography, and an index.
  • citation-type="booksimple"

    xlink:type="simple">Pancaldi, Giuliano. Volta: Science and Culture in the Age of Enlightenment. Princeton, N.J.: Princeton University Press, 2003. The interactions between Volta and Davy were many, and this life of Volta also contains interesting material on Enlightenment Europe. Extensive bibliography and index.

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