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Catechism of Familiar Things; Their History, and the Events Which Led to Their Discovery, A

<h2>CHAPTER XII.</h2> <h3>Spectacles, Mariner's Compass, Barometer, Thermometer, Watches, Clocks, Telescope, Microscope, Gunpowder, Steam Engine, and Electro-Magnetic Telegraph. </h3> When were Spectacles invented, and who was their inventor? It is supposed that they were first known about the thirteenth century, and invented by a monk of Pisa, in Italy, named [95]Alexander de Spina. Spectacles are composed of two circular pieces of glass set in a frame. What are these glasses called? Lenses. They are either convex or concave, according to the kind of sight requiring them. Old people, and those who can only see things at a distance, from the flatness of the eye, which prevents the rays of light converging so as to meet in the centre, require convex lenses. People who can only distinguish objects when viewed closely, from the eye being too convex, require concave lenses to counteract it by spreading the rays, and thus rendering vision distinct. <div class="blockquot">Convex, rising outwardly in a circular form; opposite to concave. Concave, hollow; round, but hollow, as the inner curve of an arch, &c. Converging, tending to one point from different parts. Vision, the faculty of seeing. </div> What is the Mariner's Compass? A most useful and important instrument, by the aid of which the navigator guides his ship on the sea, and steers his way to the place of his destination. The inventor of the Mariner's Compass is not known, nor the exact time of its introduction; it was employed in Europe in navigation about the middle of the thirteenth century, and has been in use more than five hundred years. The Chinese are said to have been acquainted with it much earlier, but no reliance can be placed on their dates. The power of the loadstone to attract iron was known to the ancient Egyptians, but it was not applied to any practical purpose. <div class="blockquot">Navigator, one who guides a ship. Steer, to direct or guide a vessel in its course. Destination, the place to which a person is bound. Practical, capable of practice, not merely speculative. </div> What is the Loadstone? An ore of iron which possesses the peculiar property of attracting iron, namely, of drawing it in contact with its own mass, and holding it firmly attached by its own power of attraction. A piece of loadstone drawn several times along a needle,[96] or a small piece of iron, converts it into an artificial magnet; if this magnetized needle is carefully balanced, it will turn round of itself, till its end points towards the North. The magnetized needle also possesses the power of attracting iron, and of communicating this power to another piece of iron or steel, similar to that of the loadstone itself. <div class="blockquot">Contact, touch. Magnetized, rendered magnetic. </div> Describe the Mariner's Compass. The Mariner's Compass consists of a circular box, enclosing a magnetized bar of steel, called the needle, carefully balanced on an upright steel pivot, and having that end which points to the North shaped like the head of an arrow; attached to this needle, and turning with it, is a card on which are printed the divisions of North, South. East, and West; called the points of the compass. By simply looking at the position of the needle, the mariner can see the direction in which his vessel is sailing, and regulate his helm accordingly. <div class="blockquot">Helm, the instrument by which a ship is steered, consisting of a rudder and tiller. </div> What is a Barometer? An instrument for measuring the weight of the atmosphere, which enables us to determine the changes of the weather, the height of mountains, &c. It consists of a glass tube hermetically sealed at one end, filled with mercury, and inverted in a basin of mercury; according to the weight of the atmosphere, this mercury rises or falls. How is the Hermetic seal formed? By heating the edges of a vessel, till they are just ready to melt, and then twisting them closely together with hot pincers, so that the air may be totally excluded. The word is taken from Hermes, the Greek name for Mercury, the heathen god of arts and learning, and the supposed inventor of chemistry,[9] which is sometimes called the hermetical art; or perhaps from Hermes, an ancient king of Egypt, who was either its inventor, or excelled in it. <div class="footnotes">[9] See Chapter XVIII., article Chemistry. </div> [97] What is Mercury? Quicksilver, or mercury, is a white fluid metal, the heaviest except platina and gold; it readily combines with nearly all other metals, and is used in the manufacture of looking-glasses, barometers, thermometers, &c.; in some of the arts, and in the preparation of several powerful medicines. It is found in California, Hungary, Sweden, Spain, China, and Peru. The quicksilver mine of Guança Velica, in Peru, is one hundred and seventy fathoms in circumference, and four hundred and eighty deep. In this profound abyss are seen streets, squares, and a chapel, where religious worship is performed. The quicksilver mines of Idria, a town of Lower Austria, have continually been wrought for more than 300 years. The vapor which is continually arising from the mercury is very hurtful to the miners, who seldom survive many years. <div class="blockquot">Abyss, a gulf, a depth without bottom. </div> In what state is Mercury usually found? Either native, or in the form of ore; it is often found mixed with silver, but more frequently with sulphur in the form of sulphuret, which is decomposed by distillation. Running mercury is found in globules, in America, and is collected from the clefts of the rocks. Mercury has the appearance of melted silver; it is neither ductile nor malleable in this state; it is a substance so volatile, when heated, that it may be evaporated like water; it is always seen in a fluid state, even in temperate climates, as a very small portion of heat is sufficient to preserve its fluidity. It is used to separate gold and silver from the foreign matter found with those metals. Calomel, a valuable medicine, and vermilion, a color, are both preparations of mercury. <div class="blockquot">Globules, small particles of matter having the form of a ball or sphere. </div> What is a Thermometer? [98] An instrument for measuring temperature. It consists of a fine glass tube, terminated at one end in a bulb, usually filled with mercury, which expands or contracts according to the degree of heat or cold. On the scale of the Fahrenheit thermometer, the freezing point of water is marked 32° and the boiling point at 212°. In both the Centigrade and the Reaumur scales the freezing point is at 0, and the boiling point at 100° in the Centigrade and at 80° in Reaumur's. The invention of this instrument dates from about the close of the sixteenth century; but it is not known by whom it was first brought into use. <div class="blockquot">Terminated, finished, ended. </div> When and by whom were Watches and Clocks invented? Watches were invented about the year 1500, but who was the inventor is disputed. They were, however, of little value as time-keepers, before the application of the spiral spring as a regulator to the balance; the glory of this excellent invention lies between Dr. Hooke and M. Huygens; the English ascribing it to the former, the Dutch, French, &c., to the latter. Some assert that pocket-watches were first made about 1477, at Nuremberg, in Germany. The most ancient clock of which we possess any certain account, was made in 1634 by Henry de Wycke, a German artist; it was erected in a tower of the palace of Charles V., king of France. The pendulum was applied by Huygens, in 1656. What is a Pendulum? A weight so suspended from a fixed point that it may easily swing backward and forward; its oscillations are always performed in equal times, provided the length of the pendulum and the gravity remain the same. It is said that the idea of employing the pendulum for the measurement of time, was first conceived by Galileo, while a young man, upon his observing attentively the regular oscillations of a lamp suspended from the roof of a church in Pisa. It was not, however, till the time of Huygens that a method was devised of continuing its motions, and registering the number of its oscillations. [99] <div class="blockquot">Oscillation, a swinging backward and forward. Gravity, the tendency of a body toward the centre of the earth. Registering, recording. </div> <ANTIMG src="images/image_09.jpg" alt="CHARCOAL BURNING." width-obs="527" height-obs="383" /> CHARCOAL BURNING. <ANTIMG src="images/image_10.jpg" alt="GOLD MINERS WASHING ORE." width-obs="526" height-obs="391" /> GOLD MINERS WASHING ORE. To whom is the invention of Gunpowder ascribed? Most authors suppose it was invented by Bartholdus Schwartz, a monk of Goslar, a town of Brunswick, in Germany, about the year 1320; it appears, however, that it was known much earlier in many parts of the world, and that the famous Roger Bacon, who died in 1292, knew its properties; but it is not certain that he was acquainted with its application to fire-arms. Who was Roger Bacon? A learned Franciscan, born at Ilchester, England, in 1214. He studied at Oxford, and afterwards became professor at that great University. He was familiar with every branch of human knowledge, but was especially distinguished for his extraordinary proficiency in the natural sciences. To him we owe the invention of the telescope; that of gunpowder is ascribed to him, as stated above, although we have no evidence to show whether he discovered its ingredients himself, or whether he derived the knowledge from some ancient manuscripts. Bacon suffered some from the ignorance of the age in which he lived, many of his experiments being looked upon as magic. He died at Oxford in the year 1294. What is understood by Magic? Magic is a term used to signify an unlawful and wicked kind of science, depending, as was pretended, on the assistance of superhuman beings and of departed souls. The term was anciently applied to all kinds of learning, and in particular to the science of the Magi or Wise Men of Persia, from whom it was called magic. Natural magic is no more than the application of natural active causes to passive things or subjects, to produce effects apparently supernatural. <div class="blockquot">Supernatural, beyond the powers of nature; miraculous. </div> [100] Of what is Gunpowder composed? Of saltpetre,[10] sulphur, and charcoal, mixed together and powdered; its explosive force when fired, is owing to the instantaneous and abundant liberation of gaseous matter by the intense heat resulting from the action of the combustibles upon the saltpetre. It is not known by whom it was first applied to the purposes of war, but it is certain that it was used early in the fourteenth century. Cannons were used at the battle of Cressy, in 1346; small guns, or muskets, were introduced into the Spanish army in 1521. <div class="footnotes">[10] See Chapter XIII. </div> <div class="blockquot">Explosive, bursting out with violence and noise. Liberation, a setting at liberty. </div> Is not Gunpowder highly combustible? So combustible is gunpowder, that a single spark of fire, lighting upon any of it, will cause it to explode with immense force; and instances have occurred, when any store or magazine of it has taken fire, that have been attended with the most fatal effects. It is useful to the miner and engineer as a ready means of overcoming the obstacles which are presented in their search for mineral treasures, and in procuring materials for building. From many passages in the ancient authors, there is reason to suppose that gunpowder, or a composition extremely like it, was known to them; but it does not appear to have been in general use, and the invention of fire-arms is comparatively modern. Dynamite, a recent invention, has a still greater explosive force than gunpowder. <div class="blockquot">Engineer, one who works or directs an engine. Obstacles, hinderances, obstructions. </div> What is Saltpetre? A bitter kind of salt, called by the ancients nitre, but more commonly among us saltpetre. It is composed of nitric acid and potassa.[11] It is found in earthy substances; sometimes native or pure, in the form of a shapeless salt. Vast quantities [101]are found in several of the marly earths of the East Indies, China, Persia, and also in South America. In India it is found naturally crystallized, and forming thin crusts upon the surface of the earth. It is especially abundant in the United States, being found in immense quantities in the limestone caves in the south-western States. <div class="footnotes">[11] See Potash, Chapter VII., article Glass. </div> What do you mean by Marly? Consisting of marl, a kind of earth composed of different proportions of clay and carbonate of lime; it is much used for manure. There are several different-colored marls, each possessing different qualities. The most common are the red and the white, though there are grey, brown, blue, and yellow colored marls. What is a Telescope? An optical instrument, which serves for discovering and viewing distant objects, either directly by glasses, or by reflection. The invention of the telescope is one of the noblest and most useful of which modern ages can boast, since by means of this instrument the wonderful motions of the planets and fixed stars, and all the heavenly bodies, are revealed to us. The honor of the invention is much disputed; it is certain, however, that the celebrated Galileo was the first who improved the telescope so as to answer astronomical purposes. The name is formed from two Greek words, one signifying far, the other to observe. <div class="blockquot">Optical, relating to Optics, the science of vision. Astronomical, relating to Astronomy. </div> Who was Galileo? A most eminent astronomer and mathematician, born at Florence, in Italy. His inventions and discoveries in Astronomy, Geometry, and Mechanics, contributed much to the advancement of those sciences. He died in 1642. <div class="blockquot">Astronomer, one versed in Astronomy. Mathematician, one versed in Mathematics; a science which treats of magnitude and number. </div> [102] What is Astronomy?[12] That science which teaches the knowledge of the heavenly bodies, with the nature and causes of their various phenomena. <div class="footnotes">[12] See Chapter XVIII. </div> What is Geometry? An ancient, perfect, and beautiful science, which treats of the relations and properties of lines, surfaces, and solids. What is meant by Mechanics? The science which investigates the laws of forces and powers, and their action on bodies, either directly or by machinery. When the term mechanic is applied to a person, it means one skilled in mechanics, accustomed to manual labor. <div class="blockquot">Investigate, to search, to inquire into. Manual, performed by the hand. </div> What is a Microscope? An optical instrument, by means of which very minute objects are represented exceedingly large, and viewed very distinctly according to the laws of refraction or reflection. Nothing certain is known respecting the inventor of microscopes, or the exact time of their invention, but that they were first used in Germany, about 1621. <div class="blockquot">Minute, small, diminutive. Refraction, a change in the direction of a ray of light, when it passes through transparent substances of different densities. Reflection, a turning back of a ray of light after striking upon any surface. </div> What is the Steam Engine? A machine that derives its moving power from the force of the steam produced from boiling water, which is very great, especially when, as in the steam engine, it is confined within a limited compass: this useful machine is one of the most valuable presents that the arts of life have received from the philosopher, and is of the greatest importance in working mines; supplying cities with water; in working metals; in many mechanical arts; and in navigation. By the aid of steam, vessels [103]are propelled with greater swiftness than those which are wholly dependent on the winds and tides; and thus trade is facilitated, and we are enabled to communicate with distant lands in a much shorter space of time than was formerly consumed. On land, railroads are constructed, on which steam carriages run with astonishing rapidity, so that a journey which by coach and horses formerly required two or more days, may now be performed in four or five hours. <div class="blockquot">Mechanical, belonging to Mechanics. </div> To whom are we indebted for its invention? Its invention is by most writers ascribed to the Marquis of Worcester, an Englishman, about 1663; but it does not appear that the inventor could ever interest the public in favor of this, or his other discoveries. The steam engine of Captain Savery, also an Englishman, is the first of which any definite description has been preserved. It was invented in 1698. Since that period it has been successively improved by various persons, but it is to Mr. Watt and Mr. Boulton, of England, that it is indebted for much of its present state of perfection. By whom was the Steam Engine first applied to the purposes of Navigation? By John Fitch, of Pennsylvania. From papers in the historical collections of Pennsylvania, it appears that the first successful experiments were made at Philadelphia, in 1785, three years before the attempts at Falkirk, and on the Clyde, in Scotland. The boat made several trips on the Delaware and Schuylkill rivers, but owing to repeated accidents to her machinery, and the want of funds and competent mechanics for the necessary repairs, she was abandoned. In 1807, Robert Fulton, also of Pennsylvania, made his first experimental trip on the Hudson River, with complete success. To this distinguished and ingenious American justly belongs the honor of having brought navigation by steam to a state of perfection. In 1819, the first steamship crossed the Atlantic from Savannah [104]to Liverpool; and in 1838, a regular communication by steamship was established between Great Britain and the United States. Since that period, ocean navigation by steam-vessels has made rapid progress, and, at the present time, numbers of steamers connect our various seaports with those of other nations, and with each other. What is the Electro-Magnetic Telegraph? An instrument, or apparatus, by means of which intelligence is conveyed to any distance with the velocity of lightning. The electric fluid, when an excess has accumulated in one place, always seeks to transfer itself to another, until an equilibrium of its distribution is fully restored. Consequently, when two places are connected by means of a good conductor of electricity, as, for instance, the telegraphic wire; the fluid generated by a galvanic battery, if the communication be rendered complete, instantaneously traverses the whole extent of the wire, and charges, at the distant station, an electro-magnet; this attracts one end of a lever, and draws it downward, while the other extremity is thrown up, and, by means of a style, marks a slip of paper, which is steadily wound off from a roller by the aid of clock-work. If the communication is immediately broken, only one wave of electricity passes over, and a dot is made upon the paper; if kept up, a line is marked. These dots and lines are made to represent the letters of the alphabet, so that an operator employed for the purpose can easily read the message which is transmitted.—The Electro-Magnetic Telegraph was first introduced upon a line between Baltimore and Washington, by Professor Morse, in 1844; at the present time, it is in successful operation between nearly all the important cities and towns of the United States and of Europe. <div class="blockquot">An Electro-Magnet is a piece of soft iron, rendered temporarily magnetic by being placed within a coil of wire through which a current of electricity is passing. </div> [105] <hr style="width: 65%;" /> <div style="break-after:column;"></div>

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