Science, Invention, Discovery. the upper portions of the atmosphere pressing upon and condensing the lower strata. One half the actual weight of the atmosphere is comprised within the space of the lower five miles of its total height, the remaining thirty miles in height containing the other half. The air is highly compressible and elastic, and its volume diminishes inversely as the pressure increases. This accounts for the facility of setting it in motion and its velocity. Like fluids, it presses equally in every direction, and when it comes in contact with a more expanded and therefore lighter portion of air, it pushes it up and occupies its place, producing currents of air and winds when 't flows in streams, and sounds when it is thrown into vibrations or undulations. The air absorbs heat from both the earth and the sun and moderates extremes of temperature day and night and summer and winter. It absorbs about 40% of the heat of a sunbeam when the sun is at zenith. Alcoholic Drinks. The number of elevation above the sea increases, owing to alcoholic drinks is surprisingly large and varied. The following are the principal: Agua ardiente, made in Mexico, from the fermented juice of agave; arrack, made in India from the juice of the palm and from rice; araka, made in Tartary, from fermented mare's milk; araki, made in Egypt from dates; brandy, made in nearly all wine countries from wine and from fruits; Geneva or Holland gin, made in Holland from malted barley or rye, rectified on juniper berries; gin made in England from malted barley, rye, or potatoes, and rectified with turpentine; goldwasser, made at Dantzic from various kinds of corn and rectified with spices; kirchwasser, made in Switzerland from the Mahaleb cherry; lau, made in Siam from rice; maraschino, made in Dalmatia from the Macarska cherry; Mahwah arrack, made in India from the flowers of the madhuca tree; rum, made in the West Indies and South America from cane sugar and molasses; rakia, made in Dalmatia from the husks of grapes, mixed with aromatics; rossolio, made at Dantzic from a compound of brandy with certain plants; slatkai-trava, made at Kamtschatka from a sweet grass; show-choo, made in China from the lees of rice wine; trosta, made in the Rhenish provinces from the husks of grapes fermented with barley and rye; tuba, made in the Philippine Islands from palm wine; vino mescal, made in Mexico by distilling the fermented juice of the agave; whisky, made in Scotland, Ireland and United States from raw and malted grain, and south of France from sloes. Air. The gaseous envelope of the earth is composed of oxygen and nitrogen in the ratio of 21 to 79 respectively; a small percentage of watery vapor and carbonic acid gas, and a trace of other gases. Our planet has two coverings. The first, a partial one, is the water, distributed as lakes and seas. The second covering is the air or atmosphere, rising upwards to an altitude somewhat above thirty-five miles; it is a true, aeriform ocean surrounding our earth and has upon its upper surface waves and tides, and, throughout its mass, currents flowing in constant and variable directions, precisely as those of the ocean comport themselves; it is held down to the surface of the earth by attraction, and rotates with the planet; its density varies with its actual height at the place of observation, of which the barometric pressure is the evidence. This pressure diminishes as the Acoustics.- The doctrine of the different sounds of vibrating strings, and the communication of sounds to the ear by the vibration of the atmosphere, was probably first explained by Pythagoras, about 500 B. C. Mentioned by Aristotle, 330 B. C. The speaking trumpet is said to have been used by Alexander the Great, 335 B. C. The discoveries of Galileo were made about 1600 A. D. The velocity of sound was investigated by Newton before 1700. Galileo's theorem of the harmonic curves was demonstrated by Dr. Brook Taylor, in 1714; and further perfected by D'Alembert, Euler, Bernoulli, and LaGrange, at various periods of the eighteenth century. Algebra.-Where Algebra was first used, and by whom, is not precisely known. Diophantus first wrote upon it, probably about 350 A. D.; he is said to be the inventor. Brought into Spain by the Saracens, about 900; and into Italy by Leonardo of Pisa, in 1202. The first writer who used algebraical signs was Stifelius of Nuremberg, in 1544. The introduction of symbols for quantities was by Francis Vieta, in 1591, when algebra came into general use. The binomial theorem of Newton, the basis of the doctrine of fluxions, and the new analysis, 1665. Descartes applied al gebra to geometry about 1637. Almanacs. The Egyptians computed time by instruments. Log calendars were anciently in use. The word almanac is of Saxon origin. Michael Nostradamus, the as trologer, wrote an almanac in the style of Mer- | which gold and silver are usually alloyed, are lin, 1556. The first published is said to have convertible into oxides by exposure to atmosbeen by Martin Hykus, at Buda in 1470. The pheric air at a high temperature, whereas the first almanac in England was printed at Oxford, precious metals remain unacted upon. in 1673. Anatomy. The human body was studied by Aristotle about 350 B. C., and its structure was made part of the philosophical investigations of Plato and Xenophon; it became a branch of medical education, under Hippocrates about 420 B. C. Erasistratus and Herophilus first dissected the human form, and may be regarded as the fathers of anatomy; it is said that they practiced upon the bodies of living eriminals about 300 and 293 B. C. Galen, who died 193 A. D., was a great anatomist. In England the schools were long supplied with bodies unlawfully exhumed from graves; and until 1832 the bodies of executed murderers were ordered for dissection. Pope Boniface VIII. forbade the dissection of dead bodies, 1297. The first anatomical plates, designed by Titian, were employed by Vesalius, about 1538. The discoveries of Harvey were made in 1616. The anatomy of plants was discovered in 1680. Angling. The origin of this art is involved in obscurity; allusion was made to it by the Greeks and Romans, and in the most ancient books of the Bible, as Amos. It came into general repute in England about the period of the reformation. Winkin de Worde's Treatyse of Fysshinge, the first book printed on angling, appeared in 1496. Isaac Walton's book was printed in 1653. Arithmetic.- Where first invented is not known, at least with certainty. It was brought from Egypt into Greece by Thales, about 600 B. C. The oldest treatise upon arithmetic is by Euclid, about 300 B. C. The sexagesimal arithmetic of Ptolemy was used A. D. 130. Diophantus of Alexandria was the author of thirteen books of arithmetical questions (of which six are extant) in 156. Notation by nine digits and zero, known at least as early as the sixth century in Hindostan introduced from thence into Arabia, about 900, into Spain 1050, into England 1253. Arithmetic of decimals invented 1482. First work printed in England on arithmetic was by Tonstall, bishop of Durham, 1522. The theory of decimal fractions was perfected by Lord Napier in 1617. -- Assaying. The assaying of silver and gold is affected by a process called cupellation. Cupels are small flat crucibles made by pressing bone ash moistened with water, into circular steel molds, and they are dried by exposure to the air. The principle upon which the operation depends is, that all metals with To assay silver by cupellation the silver is flattened and wrapped up in an envelope of lead. A muffle or oven is heated in an assay furnace and the two metals put into it. The metals melt and the lead becomes converted into an oxide, which as well as any baser metals before combined with the silver is absorbed by the substance of the cupel until at length the silver is left absolutely pure. The assaying of gold is performed, to a certain extent in a similar way, and if the gold were alloyed only with copper, the process would be as simple as that of silver assaying. Usually, however, gold contains silver, and this cannot be got rid of by cupellation, the parting process is, therefore, had recourse to; this consists in dissolving the silver by dilute nitric acid, which leaves the gold perfectly pure. Iron ores are assayed by separating the oxygen from the iron, by the greater affinity of charcoal for that element at high temperatures. The ore, some charcoal, and an alkaline flux are heated in a crucible; and the result is that all the impurities in the ore are made to leave the iron so that the latter is presented in a purely metallic form. Copper ores usually contain sulphur, and in order to assay them a flux is prepared of fluor spar, borax, slacked lime, argol, and niter. Automobile.- This name covers all forms of self-propelling vehicles for use on country roads or city streets, whether driven by steam produced by the combustion of fuel, stored steam, compressed air, oil or gasoline engines, or by electric motors taking current from accumulators. Automobiles are not of recent origin, as many generally suppose, but date back to the early days of the steam engine, to the time of Sir Isaac Newton, who, in 1680, proposed a form of steam carriage which embodied the essential features of a steam automobile. In 1790 Nathan Read patented and constructed a model steam carriage. But the first actual experiments were made in 1769, by a French army officer, Nicholas Cugnot, who built a three wheel carriage. In America, Oliver Evans, as early as 1786, suggested a form of road wagon to be propelled by steam. In 1803 Richard Trevithick built a full sized carriage which was exhibited in London, having driven itself 90 miles en route from Camborne, where it was constructed. David Gurney built and operated a steam carriage in 1827, in which he made frequent and long journeys, covering as much as 85 miles in 10 hours. He was excelled by Walter Hancock who established several stage lines. Since 1895 the construction of automobiles has been carried on with great energy, and many improvements have been made. So far the most satisfactory results have been obtained with the steam, oil, and electric carriages. In tire construction the pneumatic tire occupies the first place in public favor, although solid rubber tires are largely employed. The highest speed is obtained by use of light oils, preferably gasoline; steam motors are most successfully used with heavy trucks and vans; the electric motor has given the best satisfaction when employed on vehicles for city cab and carriage work and short radius runs. Æolian Harp was the invention, it is believed, of Athanasius Kircher, who lived in the seventeenth century, and it is so called from Eolus, the god or ruler of the winds. It is a simple musical instrument, the sounds of which are produced by the vibrations of strings moved by wind. It may be composed of a rectangular box made of thin boards, five or six inches deep and about the same width, and of a length sufficient to extend across the window it is to be set at, so that the breeze coming in can sweep over it. At the top of each end of the box a strip of wood is glued, about a half-inch in height; the strings are then stretched lengthwise across the top of the box, and may be tuned in unison by means of pegs constructed to control their tension, as in the case of a violin. The sounds produced by the rising and falling wind, in passing over the strings, are of a drowsy and lulling character, and have been beautifully described by the poet Thomson as supplying the most suitable kind of music for the Castle of Indolence. and to invent a means for the propulsion of balloons, and in the latter year Captains Renard and Krebs produced an air ship which was considered the crowning effort in this line of invention. This ship was a cigarshaped balloon, carrying a platform, on which the steering and propelling apparatus was placed. The balloon was made of strong silk and covered with a light netting of cords. It was 197 feet long and 39 feet in diameter. To the netting was suspended the platform, 131 feet long and 10 feet broad, on the front of which was fixed the propeller, a screw of light, wooden framework and air-tight cloth. The rudder was at the rear of the platform. propeller was driven by electricity, generated by a dynatno, which was in turn driven by stored electricity. The first ascension of this ship fully satisfied the most sanguine expectations of its builders. It was driven seven miles and back in the space of forty minutes, and obeyed fully every movement of the rudder. During the siege of Paris, in the Franco-German war of 1870-71, ballooning was extensively used by the besieged for communication with the outer world, and also by the besiegers for military purposes, and since that date military ballooning has become an important subject of study and experiment by soldiers. The American Clocks and Watches.The first attempt to manufacture watches or clocks on a large scale in America was made by Eli Terry, a Connecticut Yankee, who invented wooden wheels for clocks in 1792. In 1837 Chauncey Jerome, of Massachusetts, first applied machinery to the making of metalwheeled clocks, and as a result drove the wooden-wheeled clocks out of the market. The manufacture of watches by machinery, which has since become such an important business, was begun at Roxbury, Mass., in 1850, and was continued there until 1854, when the works were removed to Waltham. Archimedes, Principle of. — Archimedes, the most celebrated of ancient mathematicians, was born at Syracuse about 287 B. C. He is said to have been a kinsman of King Hiero, though he does not seem to have held any public office, but devoted himself en Aerial Navigation.- Pilatre des Rosiers made the first balloon ascension at Paris, November 21, 1783. His balloon was inflated with heated air. December 1, 1783, an ascension was made by M. Charles, a professor of Natural Philosophy, at Paris, and at about the same time successful ascensions were also made by Messrs. Rittenhouse and Hopkins, of Philadelphia, hydrogen gas being used in these instances for inflating purposes. The valve at the top of the balloon, and the hoop attached to the balloon with netting, by which is sus-tirely to science. He is the only one of the pended the car, are the inventions of M. Charles. In 1785 a successful passage of the English Channel was made by M. Blanchard, the first professional aeronaut, and an American traveler named Dr. Jeffries. The use of ropes for the purpose of steadying balloons was first adopted by M. Gay-Lussac, in 1803. From 1852 to 1884 French, German, and American aeronauts labored with degrees of success to improve the method of construction ancients who contributed anything satisfactory on the theory of mechanies and on hydrostatics. He first established the truth that a body plunged in a fluid loses exactly as much of its weight as is equal to the weight of the fluid displaced by it. This is one of the most important principles in the science of hydrostatics, and is called by his name. It was by this law that he determined how much alloy the goldsmith, whom Hiero had commissioned |