« PreviousContinue »
standard galvanometer. In the one represented, the pivoted, crescent-shaped core, attached to the pointer, is drawn into a curved coil, the counteraction being a hairspring. Ammianus Marcellinus, d. ab. 390. Roman historian of Greek birth. His first 13 books, from A. D. 96, are lost; the remaining part covers the years 353–378, and is valued as accurate and impartial, but not for its Latinity. i Ammocoetes. See LAMPREYs. Ammon, AMEN, or AMUN. Egyptian god, identified by Greeks with Zeus (Jupiter); local deity of Thebes, worshiped also on the oasis of Siwah, or Ammonium, in the Libyan desert; sometimes represented as a ram. Ammon. Semitic tribe east of the Jordan, descended from Ben-Ammi, son of Lot; often at war with Israel, and defeated by Jephthah, by several of the kings, and by Judas Maccabaeus. Ammon, CHRIstoph FRIEDRICH, Vox, 1766–1850. German rationalist, prof. at Göttingen and Erlangen, court preacher at Dresden 1813–49, and a prolific writer. Ammonia. NH,. Sp. gr. 0.59, liquefies at –40°C. or 10 Atm. pressure. Sp. gr. liq. 0.62. Bpt.-33.7°C.,749 mm. Solid —75° C. at 20 Atm. pressure. Sp. H. 0.508. Colorless, suffocating gas, disc. by Priestley 1774, made by decomposing am: monium sulphate in water with lime. Does not support animal life or combustion, but burns in oxygen. One volume of water will dissolve 670 volumes of the gas, and has sp. gr. 0.875. This solution of the gas in water is what is sold under the name of ammonia, or spirits of hartshorn. The gas can be compressed to liquid by 125 to 150 lbs. pressure and comes into the market in metallic cylinders, for the manufacture of ice. Its solution is used for cleaning purposes, and in medicine to relieve the pain of the stings of poisonous, insects, to irritate the skin, either undiluted or combined with oily matters, to restore consciousness in fainting, and as a stimulant of the heart; for this latter purpose its carbonate is preferable. Ammonia Alum. (NH,)Al(SO,),.12H.O. Made by bring. ing ammonium and aluminium sulphates together in molecular proportions. It closely resembles ordinary alum in its proper
Ammonium. Hypothetical compound, the composition of which is assumed to be NH,. In the ammonium salts, examples of which are NH,Cl,(NH,),SO, the group of atoms, NH, acts as a metal; for this reason it is given a name ending in um, as is customary in the designation of metals.
Ammonium Acid Carbonate. See AMMONIUM BICARBONATE.
Ammonium Amalgam. Substance having a metallic luster, resembling in general the other amalgams. It is very unstable, but has been obtained in crystalline form at a low temperature. It is made by pouring a solution of ammonium chloride upon sodium amalgam. The product is voluminous and swells up during the reaction. It is about twenty times the volume of the sodium amalgam. Ammonium Bicarbonate. Primary ammonium carbonate, NH, HCO,. Made by treating ammonium carbonate with on dioxide. It is used in the manufacture of baking powel's. Ammonium Carbonate. (NHA),CO,. Made commercially by heating together ammonium chloride, or sulphate and
composes at 58°C., yielding carbon dioxide, water, and ammonia. It is used in the manufacture of baking powders. Ammonium Chloride, or SAL AMMONIAC, NH,Cl. Formerly obtained from Egypt, being extracted by sublimation from salt and camel's dung. At present its principal source is from the ammoniacal liquor of the gas-works. It has a sharp, salty taste, is soluble in water and sublimes on being heated. It is used in medicine.
Ammonium Compounds. Organic compounds in which one or more of the hydrogen atoms of the group, ammonium (NH.), is conceived to be replaced by an organic group, as in NCH, H.I., methylammonium iodide.
Ammonium Hydroxide (SPIRITs of HARTSHORN). NH,OH. If ammonia be passed into water a solution is obtained having the odor and characteristics of the gas; it is strongly alkaline and has the properties of a base. On account of its close resemblance to solutions of metallic o it is believed to contain the compound, NH, OH. It is sold under the name of AMMONIA (q.v.).
Ammonium Magnesium Phosphate. UM AMMONIUM PHOSPHATE. Ammonium Nitrate. NH, NO,. nitric acid with ammonium hydroxide. It is very soluble in water and can be readily obtained in crystals. It is used for the preparation of nitrous oxide, and as a constituent of certain explosives, as Ammonite, Bellite and Roberite. A small quantity occurs in the atmosphere. Ammonium Nitrite. NH, NO,. On being heated it is decomposed into water and free nitrogen; it, therefore, furnishes a method for the preparation of nitrogen. Ammonium Phospho-molydate. (NH,),.PO,.12MoC),. Yellow substance, insoluble in water and in dilute acids. It is formed by adding a nitric acid solution of ammonium molybdate to a solution of phosphoric acid or a phosphate. This surnishes a valuable means for detecting phosphoric acid, and hence is used extensively in analytical operations.
Ammonium-sodium Phosphate. NIUM PHOSPHATE.
Ammonium Sulphate. scale for use as a fertilizer. and crystallizes in long, flattened, six-sided prisms. MONIACAL LIQUOR. Ammonium Sulphide. (NH,),S. Made by passing sulphuretted hydrogen into ammonium hydroxide until it is saturated, then a similar volume of ammonium hydroxide is added. It is used in chemical analysis to precipitate the metals of the ammonium sulphide group. When first made, it is a colorless liquid of a disagreeable odor. Upon standing it becomes yellow, due to the formation of the polysulphides (NH,),S, (NH,),S, (NH,).S., and (NH,),S,. Ammonium sulphocyanate, or THIOCYANATE. NH,S : C.N. Ammonium salt of sulphocyanic acid, prepared by the action of ammonia and alcohol upon bisulphide of carbon. White plates easily soluble in water. See SULPHOCYANIC ACID. Ammonius Saccas, d. ab. 241. Alexandrian philosopher, founder of the Neo-platonic school. Ammunition. Fuel for guns and small-arms, is classified as metallic and non-metallic and fixed, rim and center fire for small-arms, machine, and rapid-fire guns; armor-piercing shot,
Made by neutralizing
(NH,),SO,. Prepared on a large It is soluble in 2 parts of water See AM
Ammunition in Section.
1, Steel-shell; 2. Shrapnel: 3, Case-shot: 4, Common shell; 5, Complete cartridge.
canister, gase-shot, grape-shot, multicharge, Palliser-chilled shot, shells (common, and armor-piercing) and shrapnel. It formerly indicated military stores and provisions. Ammunition Box. Specially constructed and protected for the safe and convenient transportation of ammunition. Ammunition Tubes. In modern war-ships thick hollow steel forgings to protect ammunition in transit to battery.
Amnesia. Loss of memory; more specifically, a pathological condition in which memory-pictures of words are lost or deranged; a form of APHASIA (q.v.).
Amnesty. Act of oblivion, granted generally to a community or class of political offenders.
Amnion. Formed as the body wall of embryo of higher vertebrates grows up and envelops the back of the embryo by the union of the folds as they meet. The true or inner amnion forms a bag, filled with amniotic liquid in which the embryo floats. It is popularly known as the “bag of waters.” The outer amnion is at first a perfectly spherical shell surrounding the true amnion and the yolk sac. From the latter it ultimately splits entirely away and becomes attached to the eggshell or chorion. That of insects is formed in the same way as in vertebrates, and similarly overlies the neural plate, which becomes the ventral part of the insect and the dorsal part of the vertebrate.
Amniota. Birds, reptiles, and mammals collectively, as developing an amnion during embryonic life.
Amoeba. Proteus animalcule, so called because its form of body is always changing, owing to the fact that pseudopodia are formed and retracted at will from any part of the surface. It is a naked rhizopod and represents a single cell, having a clear, firm ectosarc and a fluid, granular endosarc, with a nucleus imbedded in the former. It multiplies by simple division, which is preceded by division of the nucleus, so that each daughter amoeba is nucleated from the start. This
animal eats by simply allowing its food (which is vegetable, sometimes algae, sometimes bacteria, etc.) to sink into the substance of its body or by inclosing it with its protoplasmic pseudopods. Then the albuminous parts are digested out, and assimilated by being converted into a part of the protoplasm of the amoeba, while the indigestible ceilusose wall and starchy contents are ejected, from whatever part of the body happens to be hind most. When moving, it causes a part of its substance to flow out in any direction (forming a pseudopod), and the rest of the body flows into this pseudopod, swelling it up and converting it into the body of the amoeba. There seem to be no organs, no nerves, no stomach, etc., present: yet the animal can perceive the presence of food, can travel, digest, reproduce, successfully maintain itself, and do all that protoplasm in any animal can do. It can be killed or destroyed, but never dies of old age. It simply grows, and then multiplies by splitting into two halves, which are young amoebae. Ammoploea. See AMCEBINA and ARCELLINA. Amoebiformes. Rhizopods like the amoeba. See Lobos.A.
Amoebina, , or NUDA. Order of Lobosa, including the amoeba, whose body is a naked cell; hence the names.
Amoebodont Dentition. Molar teeth of mammals, that have the tubercles on their crowns alternately placed. These types have been distinguished by Cope: palaeotheriodont, symborodont, bathmodont, loxolophodont, and hippodont.
Amoebosporidia. Sub-class of Gregarines, including the genus Ophryocystis, parasitic in Tenebrionidae beetles. It is amoeboid, multinucleate when large, and divides simultaneously into several uninucleate parts, which conjugate and encyst, and binarily produce six nuclei, two of which conjugate and produce one spore.
Amon Ra. Egyptian deity, originally the local god of Karnak, and probably the god of Harvest. The political ascen
Ampère, JEAN JACQUES ANToINE, 1800–1864. French literary historian and critic; member of the Academy from 1847. French Literature of the Middle Ages, 1841.
Ampère's Hypothesis (OF MAGNETs). That each molecule of a magnetic substance is surrounded by a closed electric current, and that magnetization consists in rendering parallel the axes of all these currents. The resultant of the actions of such currents would be equivalent to that of a single current traversing the outside of the magnet. Thus by this hypothesis all magnetic phenomena may be referred to electro-dynamic principles.
Ampère's Laws (of THE MUTUAL ACTION OF ELECTRIC CURRENTs). I. Two currents which are parallel and in the same direction attract each other. II. Two currents parallel but in opposite directions repel each other. III. When two currents cross at a point, they attract each other if they both approach the point or both recede from it. They repel each other when one approaches the intersection and the other recedes from it.
Ampère-turns. Product of the current strength by the number of turns of wire in a coil. See SATURATION, MAGNETIC.
Ampfing, BAvARIA. Here Lewis the Bavarian defeated and took prisoner his rival Frederic of Austria, 1322. Moreau began here his famous retreat, 1800.
Amphiaster. Spindle formed in the nucleus during cell division has, during the kataphase, a star at each end, composed of the metamorphosed chromatic mitom. The entire structure is termed the amphiaster or double star. Also, a form of sponge spicule consisting of two asters united by an a XIS.
Amphibia (BATRACHIA, SALAMANDERS AND FROGs). Coldblooded Vertebrates, usually with naked skin, with lungs (and also gills, at least in the î. with two chambers to the auricle in the adult and with a one-chambered ventricle to the heart. There are four pairs of aortic arches, the three anterior of which bear gills, the fourth being connected with the lungs. . The eggs usually are fertilized and develop outside the body, the young having neither amnion nor allantois. There are four orders: Gymnophioma, Labyrinthodonta, Urodela and Anura. Scientifically, this group of animals may be classed with the fishes, the two classes being the phylum Ichthyopsida. Popularly they are regarded as reptiles, the terms Salamander and Lizard being used without discrimination, and applied to apparently similar representatives of the Sauropsidan and Ichthyopsidan branches of Vertebrata.
Amphibiotica. Tribe of Pseudomeuroptera, whose larvae live in the water and breathe by tracheal gills. The May-flies (Ephemeridae) and Dragon-flies (Libellulidae) are included.
Amphiblastula. Peculiar blastula which is formed in the development of calcareous sponges. The segmentation of the sponge ovum results in a spheroidal mass of cells, that are large and granular at one end of this blastula, and are small and flagéilated at its opposite pole. . The next, stage is the pseudogastrula, followed by a return to the amphiblastula, condition, and then finally by the development of the paragastrula.
Amphibole. RSiO, Group of minerals, classed as anhy: drous metasilicates, which agree closely in crystalline form and other physical properties, and in type of chemical composition. though differing considerably in details. Among the bases present, magnesium is the most constant; others are aluminium, calcium, iron, manganese, and the alkalies. The colors range from white to black, through shades of green. The most frequent varieties are actinolite, asbestus, hornblende, pargasite, and tremolite. Amphibole in its several forms is a common ingredient in crystalline rocks.
Amphibolidae. Family of Pulmonates, of the sub-group Basommatophora. Amphicoelia. See CROCODILIA.
Amphictyonic League. Association in ancient Greece, which " met twice a year, once at Delphi and once at Thermopylae. It comprised twelve tribes, each, having two votes. These tribes seem to have combined in electing representatives to the great council, these being of two classes, the Pylagorae and the Hieromnemones. The council treated many international questions, both regarding the temples of the gods held in common and also others, such as declaring war against Persia. Two sacred wars were waged under their sanction, one 585 B.C. and the other 346 B.C., Philip of Macedon being commander in the latter. Amphidiscs. Spicules which surround the gemmules of spongolia and resemble two-toothed wheels united by an axis. Amphigasters. Series of small leaves appressed to the under side of the stem in certain Liverworts. Amphigastrula. Peculiar gastrula of sponges, which in the ostulo stage is ciliated on one-half of the ovoid. It is this pole or hemisphere which is invaginated to form the gastrula. Amphigenesis. See ALTERNATION OF GENERATIONS. Amphilestes. One, of the earliest marsupial mammals, a jaw and teeth of which have been found in the Stonesfield slate of the English Jurassic rocks. Amphimorphae. Order of birds including the flamingoes. See LAMELLIROSTRES.
Amphincura.. Group of animals including Chiton, Chaetoderma and Neomenia. Amphion. Son of Zeus and Antiope. King of Thebes. He
built the wall of Thebes by aid of a magic lyre given him by
of Tiryns. Amphiuma. See DEROTREMA. Amphora. Ancient pottery vessel used for holding wine
and other liquids; slender and cylindrical, tapering to a narrow neck with handles; tapering also to a point at the base, so that it could be set upright in the sand or mould of a cellar, or leaned against a wall. Also, smaller glass and pottery vessels of the same shape.—In botany, lower part of fruit known as pyxis, as that of Portulaca and Plantain. Amplitude. Distance through which a vibrating particle or body moves on either side of its position of rest. Also the radius of the circle of reserence of a simple harmonic motion (q.v.). Amplitude of a Star. Distance from e. or w. point of the horizon to the foot of the vertical arc passing through the body. Ampula. Ancient bellied or globular form of bottle in pottery or glass, used mainly for holding the oil required after gymnastic exercises or bath.
Ampullae. (1) Of Echinoderms. See AMBULACRAL SYSTEM. (2) Small sacs (see RHAGON) lined with choanocytes, formed on the course of the canals (incurrent and excurrent) that ramify through a sponge. The water is drawn in by the activity of the flagella of the choanocytes, which cells take their nutriment and oxygen from the water as it passes.
Amputations. Between 350 B.C., when the Hindoos performed this operation, and ab. 1550, this branch of surgery showed little advance and was a procedure justly dreaded on account of the difficulty of arresting the haemorrhage. Hot oil or pitch, or a heated iron, were the only measures used for this purpose until the tourniquet appeared, an instrument which surrounds a limb and compresses the artery supplying it. Modifications of this are still in use, and are in fact but little improved upon. The operation is performed for the removal of so y injured and diseased limbs or members. Pressure
upon the artery is always exerted on the body side of the incision and the arteries tied or twisted before its release, the flaps made so that when sewn together a surface covered with skin is left, all the injured or diseased tissue removed, and the wound dressed antiseptically. The nearer the trunk a limb is amputated and the greater the age above ab. 30 years the greater the danger. As little as possible should be removed, as the shorter an artificial limb is the more serviceable it is. Amputations of fingers or toes may be performed without the tourniquet, the arteries being too small to cause a serious loss of blood before being tied. The removal of small redundant parts is usually done with an écraseur or heated platinum wire loop. Amrita. In Hindoo mythology water of immortality, obtained by churning the ocean. Also, food of the gods. Amrith. Ancient Marathus in n. Syria; most in portant site of Phenician architectural remains, mainly discovered and made known by E. Renan, Mission de Phénicie. Amritsar. City of British India, between the Bias and Ravi rivers; principal trading center of the Punjab. Pop., 1891, 136,500. Amru-el-Kais. Arabian poet of 7th century. We have a poem of his which was one of the famous seven Moallakat, so called because they were suspended in the Kaaba at Mecca. Amsdorf, NIKOLAUs voN, 1483–1565. German reformer, one of Luther's helpers; remembered chiefly for his strange hyperbole, “Good works are hurtful to salvation.” Amsterdam. Capital of Holland and its most important commercial city, on an arm of the Zuyder Zee. Lying in great
Amulets. Objects worn as charms or preventives against witchcraft, sickness, accident, and other evils. Their use was common among primitive peoples, and the custom has come down to our times. The spur of red coral is a familiar illustration, being in current use, with other objects, among the people of s. Italy as a charm against the evil eye. Prof. Belluchi of Perugia has shown, by means of his collection of Italian amulets, that the peasants of the Campania use the same objects as charms as did their ancestors of prehistoric times. Amulets were much used by the ancient Egyptians and among the Greeks and Romans, and traces of them in the early Church exist. They are common to-day among all Mohammedan peoples, who wear charms inscribed on paper, stone, or metal, with sentences from the Koran. In China, children are o Fol. with amulets, inscribed with the Pat Kwa, or “Eight, Diagrams,” or an image of the God of Longevity, with the object of inviting long life.
Amyl. C.Hil. Group or radical which exists combined with hydroxyl in amyl alcohol, C.H.I.O.H. Known in various forms, of which the most common is the so-called iso-amyl, present in the amyl alcohol of susel oil.
Amyl Acetate. , C.H.,.(CH.COO). Liquid boiling at 148° C. and prepared by the action of amyl alcohol upon acetic acid in the presence of a water-absorbing agent; main constituent of the pear oil of trade. It has a pleasant odor and taste.
Amyl Alcohol. C.H.I.OH. Amyl hydrate. Eight isomeric amyl alcohols are possible; three are present in fusel oil. The most common is the iso-amyl alcohol (CH2)2:CH.CH, CH, OH. Poisonous liquid with a disagreeable odor, boiling at 131° C.
Amyl Bromide. C.H.I.Br. Combination of one of the amyl radicals with bromine. The common one is iso-amyl bromide, prepared from the alcohol and phosphorus bromide.
Amylene. C.Hig. Unsaturated hydrocarbon, known in various isomeric forms; liquid with low boiling point.
Amyl Ether. C.H.I.O.C.H.11. Oxide of the amyl group, prepared by action of amyl alcoholate upon amyl iodide.
Amyl Hydrate. See AMYL ALCOHOL.
Amyl Nitrite. C.H.I.N.O. Yellow liquid * ared by the action of nitrous anhydride upon ordinary amyl alcohol; used in pharmacy, and also in the preparation of diazo compounds; prescribed in medicine in cases of heart-failure. Amyloid. (1) Amorphous substance produced by action of strong sulphuric acid upon cellulose. Parchment paper consists of paper changed upon the surface into amyloid. (2) In botany, an organic vegetable substance resembling starch in its chemical reactions. Amyloplasts. Colorless protoplasmic bodies occurring in living plant cells, in which starch grains are developed; also known as starch-forming corpuscles, leucoplastids, and amylogenic bodies. Amyl Sulphuric Acid. C.H.I.OSO,OH. Produced by partial neutralization of sulphuric acid by amyl alcohol. Amyot, JACQUES, 1513–1593. Bp. of Auxerre; French translator of Plutarch and other Greek authors. Amyot, Joseph MARIE, 1718–1793. French Jesuit, missionary to China 1750. He prepared a Life of Confucius, a Tartar. Mantchu-French Dictionary, 1789–90, and by other writings and translations did much to make China better known in Europe. Amyrant, Moise, 1596–1664. French Reformed theologian. His Treatise of Predestination, 1634, set forth a modified view which was repeatedly attacked as heresy, but adopted by many English and American Calvinists. Anabaptists. Name given, disapprovingly, to those who denied the validity of infant baptism, especially the fermenting continental sects of the 16th century, some of which ran into fearful excesses of lust and cruelty. Jeremy Taylor, in his Liberty of Prophesying, 1647, excluded them, as dangerous to any state, from his scheme of toleration. Anabas. Climbing Perch, said to climb trees to ht. of 7 ft., when heavy rain is falling, and then, dropping to the ground. to wriggle back to the stream. It is enabled to
Anableps. Genus of the Cyprinodontidae, or Mud Minnow, largest of the family, attaining a length of a foot. They swim at the surface, as do the Top Minnows, the upper half of each eye out of water. A horizontal partition divides each eye into
two parts, one adapted for vision in air, the other in water. These fishes resemble some of the other Mud Minnows (e.g. Gambusia) in bringing forth their young at an advanced stage of development. They are viviparous, carnivorous, and inhabit rivers of tropical parts of N. and S. America.
Anacanthini. Order of Physoclist fishes, with soft fins; usually the pelvic fins are jugular. There are three sub-orders: Symentognathi, Heterosomata, and the Gadidae. To the first belongs the family (Scomberosocidae) of Gar-fishes and Flyingfishes. The Gars (Belome) or Bill-fish are remarkably slender and have the toothed jaws produced into a long slender snout. The Flying-fish belong to the genus Ecocoetus. These leap from the water by a smart stroke of the tail and, spreading their long pectoral fins, are able to sustain and prolong the leap for a minute or longer. To the second group belong the Flat-fishes (Pluromectidae), as the Plaice, Sole, Flounder, Halibut. They swim near the bottom on one side, and this has caused the lower eye to twist around to the upper side, the process taking place gradually in the young. To |. last group belong the §. by some authors placed with the Acanthopteri.
Anacardiaceae. Natural family of flowering plants of the class Angiospermae and sub-class Dicotyledones, comprising 56 genera and about 430 species, scattered through the tropics and the regions just beyond, both n. and s.; Sumach Family.
Anacharsis. Scythian prince, who came to Athens in quest of knowledge ab. 594 B.C.; was admitted to citizenship, traveled, and was slain on his return home. His Epistles are spurious. For “Anacharsis the Younger,” see BARTHELEMY,
Anachronism. Error in time, common to poets and artists, as when Dutch painters represent biblical characters with guns and in the dress of A.D. 1600.
Anacletus. I. Bp. of Rome before 100. II. (PIETRO PIERLEONI), anti-pope 1130–38, opposed to Innocent II.
Anaconda. Originally, large python-like serpents of both hemispheres; now, genus Eumectes, largest of the Boidae. It lives in tropical America, and subsists on large birds and small
mammals. It is brown in color, with a double row of black blotches on the back and smaller black rings on the sides.