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in a similar manner. And in 1836 Mr. De la Rue found that copies might be taken in copper of engraved copper-plates by the electro-depositing process. Faraday discovered magneto-electricity in the year 1831, by rotating a disc of copper between the poles of a magnet, and he has stated that the first successful result he obtained was so small that he could hardly detect it. This simple experiment was the origin of the magneto-electric machine, and many of these machines are now used for producing the electric light, and for depositing nickel, copper, silver, and gold, instead of by the voltaic battery. These, and other engines, thermic, magnetic, electric, &c, will probably, ere long, be constructed on as large a scale, and as many in number, as the present steam engine.

      The discovery in olden times of the attractive properties of a fragment of iron ore, was the basis of the invention of the mariner's compass, which greatly improved navigation, and led to nearly all the chief maritime discoveries which have since been made. The sciences of magnetism and geometry form the basis of the art of navigation, and have thus made our great foreign commerce possible. The discovery of magnetism enabled sailing vessels to venture freely out of sight of land, and to traverse the wide ocean with even greater safety than to sail near the shore. By its means Columbus crossed the Atlantic Ocean and discovered America. By its means also, Vasco de Gama sailed round the Cape of Good Hope and discovered a new route to India; and in the year 1500, another Portuguese Captain, Cabral, was driven across the Atlantic, discovered Brazil, and was enabled by the aid of the magnet, to send back a ship to Lisbon with news of the discovery. By its assistance also Magellan discovered Patagonia and the South Pacific Ocean; and by the completion of that voyage the Earth was first circumnavigated and proved to be a globe.

      The geographical discoveries of the Portuguese, made by means of the magnet, produced great national results; they profoundly changed the balance of power and wealth among European nations, by changing the direction of navigation and of the great streams of commerce between Europe and the East. They gave a mortal blow to Italy and the cities of the Mediterranean, by transferring Eastern commerce to Spain and Portugal: and Egypt ceased to be the greatest route of commerce from Europe to India.

      A singular contract relating to geographical research was made in the fifteenth century, between King Alphonso, of Portugal, and Ferdinand Gomez, of Lisbon, by which the latter engaged to navigate a ship and explore the coast of Africa, and to discover not less than three hundred miles of coast every year, the measurement to be made from Sierra Leone.

      Scientific discovery has in all ages been a most powerful agent of civilization and human progress. The discovery of the black liquid which a solution of nutgalls produces when mixed with green vitriol, led to the invention of writing ink; and a knowledge of the properties of ink and paper prepared the way for the invention of printing, by means of which truth and learning have spread all over the earth.

      The apparently insignificant property possessed by amber, of attracting feathers immediately after it has been rubbed, was known twenty-four hundred years ago, and afterwards led to the discovery of electricity. In later times, Dr. Franklin, by means of a kite, charged a bottle with lightning, examined it, and proved lightning and electricity to be identical. This knowledge, joined to the further discovery, that electricity would pass freely through metals, led to the modern invention of the lightning conductor, by means of which all our great buildings, ships, lighthouses, arsenals, and powder magazines are protected from lightning.

      "Coming events cast their shadows before them:" the discovery of the instant transmission of electricity along wires by Stephen Gray and Wheeler, about the year 1729, fore-shadowed the invention of the electric telegraph. About the year 1819, Oersted, a Danish philosopher, after fifteen years of study and experiment, to ascertain the relation of electricity to magnetism, discovered that if a freely suspended magnetic needle was supported parallel and near to a wire, and an electric current then passed through the wire, the needle moved and placed itself at right angles to the current. This discovery, coupled with the previous one of the electric conductivity of metals, formed the indispensable basis of all our electric telegraphs.

      Original research is very productive of new industries and inventions. The discoveries made by Volta, Faraday, and many other investigators, have led to the process of electro-plating, the use of electric lights for lighthouses, and for ocean steamships, and the great system of telegraphs. Those of Davy, Wedgwood, and others, respecting the action of light upon salts of silver, have resulted in the modern processes of photography, which are now in use almost everywhere. The discovery of zinc, by Paracelsus, has been followed by the use of that metal in galvanic batteries, and the great use of "galvanized" iron for telegraph wires, for roofing, and many other purposes. The discovery of nickel, by Cronstedt, has led to the great modern use of that metal in electro-plating, and to that of German silver in the construction of electro-plated and other articles. The discovery of chlorine, by Scheele, formed the basis of nearly all our modern processes of bleaching cotton and other fabrics. The discovery of gun-cotton and nitro-glycerine has led to the use of those substances in blasting rocks and in warfare. The discovery of oxygen, by Priestley, has enabled us to understand and improve in a great number of ways the numerous manufacturing, agricultural, and other processes in which that substance operates. Priestley made many experiments also on the absorption of gases by water, and proposed the resulting liquids as beverages; and those apparently trifling experiments have since expanded into the large manufactures of aërated waters. The discoveries of gutta-percha and india-rubber were indispensible to the great applications of those substances in telegraph cables, and in a multitude of useful articles. The discovery of chloroform and anæsthetics has led to their use for the purpose of alleviating human suffering. The discovery, by Sir Isaac Newton, of the decomposition of light by means of a prism, has led in recent times to the invention of the spectroscope; to the use of that instrument in the Bessemer steel process; to the discovery of a number of new metals, thallium, rubidium, cæsium, indium, and several others, and to the most wonderful discovery of the composition of the Sun and distant heavenly bodies.

      Even the invention of the steam-engine was partly a consequence of previous researches made by scientific discoverers. Watt, himself, stated in his pamphlet, entitled "A plain Story," that he could not have perfected his engine had not Dr. Black and others previously discovered what amount of heat was rendered latent by the conversion of water into steam. "Each mechanical advance in the steam-engine has been preceded by and the result of the discovery of some physical law or property of steam." "The first step in the invention of the steam-engine was the experimental research and the discoveries of the properties of steam by Hooke, Boyle, and Papin."^[2] Had not the steam-engine been developed, it is clear that railways, steamships, machinery, and all the other numerous uses to which that instrument is now applied, would have been almost unknown. The introduction of the steam-engine enabled abandoned Cornish mines to be relieved of water, and to be worked to much greater depths. The discoveries of nitric acid, hydrochloric acid, oil of vitriol, and washing soda, by the alchemists and early chemists in their researches, led to the erection of the numerous great manufactories of those substances which now exist in England and in other civilized countries. There is probably not an art, manufacture, or process, which is not largely due to scientific discovery, and if we trace them back to their source we nearly always find them originate in scientific research.

      So far has scientific discovery, and its practical applications to human benefit by invention, now progressed, that every one considers this to be, par excellence, the scientific age. And as discovery and invention continue to progress with accelerated speed, we are encouraged to hope, not only that scientific principles will ultimately be universally recognised as the regulators of all technical industry, but also as a fundamental basis of morality.^[3]

      "It is true that some processes of manufacture have not been consequences of abstract scientific discovery—that they originally resulted from alterations made in the rudest appliances, and that they have been directed and improved by the results of simple experience. For ages past we derived the benefit of scientific principles without a knowledge of their existence. We trod in the beaten paths of experience ignorant of the truth that we were acting in unison with fixed and certain laws. Numerous arts and processes were in extensive operation long before the principles involved in them were at all understood. The arts of enamelling and of iron smelting were known hundreds of years before we were acquainted

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