schwemmungen (Leipzig, 1883); Montreal Flood Commission Report (Montreal, 1890); Williams, On Some Effects of Land Floods in a Tidal River (London, 1891); "Storm Waves on the Great Lakes and the Ocean," in Monthly Weather Review (Washington, 1895); Work of the Weather Bureau in Connection with the Rivers of the United States (ib., 1896); Stoney, Extraordinary Floods in Southern India (London, 1898); Horton and Jackson, "The Ohio Valley Flood of March-April, 1913," United States Geological Survey, Water Supply and Irrigation Papers, No. 334 (ib., 1913).

IN'UUS. See MACAQUE.

INVAGINATION OF THE INTESTINES. See INTUSSUSCEPTION.

INVALIDES, ăn’và’led, LES (Fr., invalids). Wounded veterans of the French army, maintained at the expense of the state. The Hôtel des Invalides is an establishment in Paris where a number of these old soldiers are quartered. The institution was founded by Louis XIV in 1670. In 1811 it was reorganized; in 1832 its property was alienated and the institution made a charge upon the annual budget. The hôtel can accommodate 6000 men, but the actual number of inmates is now much smaller. The buildings of the Invalides comprise the hôtel proper, the chapel, and the dome. The hotel is an immense edifice of many courts and wings, grandiose in plan but commonplace in detail, the work of Levau and Bruand. A considerable part of the ground story is devoted to the unsurpassed National Museum of Artillery and an Historic Museum, chiefly military, and certain other portions to various services of the Ministry of War. Through the vast central court, entered from the Place des Invalides through a lofty portal of ineffective design, one passes to the chapel of St. Louis, by Levau and J. H. Mansart. This is a dignified but cheerless edifice, in three aisles with galleries, vaulted in stone and hung with battle flags. Mass was formerly celebrated here daily with military pomp by such of the Invalides as were able to attend. Beyond and built against it, and fronting south, is the Dome des Invalides, built by J. H. Mansart in 1693 as a royal sepulchral chapel, the finest domed edifice in France. Over the intersection of the arms of a Greek-cross plan inscribed in a square, rises the central dome, about 70 feet in diameter. This is built in three shells-an inner shell of stone with a large oculus, an intermediate shell of stone, and an outer shell of wood covered with lead, surmounted by a spirelike lantern. In 1861 the remains of Napoleon Bonaparte were transferred to the crypt of the dome (remodeled for this purpose by Isabelle and Visconti), and laid in a sarcophagus of porphyry. A circular opening in the floor of the crossing exposes the tomb to view.

IN/VALIDING (from invalid, Fr. invalide, invalid, from Lat. invalidus, not strong, from in-, not validus, strong, from valere, to be strong). In military phraseology a soldier is said to be invalided when he is sent home from abroad, as a result of climate, wounds, or other causes rendering him unfit for duty. In the United States he would be sent to a general hospital (see HOSPITAL), where it would be decided whether he remained in the army or be returned to civil life. English soldiers are sent to Netley Hospital for similar treatment and final disposition.

INVAR, in-vâr'. An alloy of nickel, 36 per cent, and steel, with 0.2 per cent of carbon, discovered by C. E. Guillaume, of the International Bureau of Weights and Measures, near Paris, useful in instruments for exact measurement and other scientific work, on account of its low coefficient of linear expansion practically negli gible for most purposes. This alloy has found application for wires and tapes used in geodesy for the measurement of base lines with a high degree of accuracy, and also in the form of bars for standards of length and for comparators and similar instruments of precision. In the United States Coast Survey invar tapes have been used since 1905 with considerable success, as they permit of the rapid and economical measurement of base lines with greater accuracy than with the steel tapes or bars previously employed. These tapes resemble nickel rather than steel in their appearance, being soft, bending easily, and being much less elastic than steel. They do not oxidize as readily, and, while their tensile strength is less than steel, it is greater than is necessary for the measurement of base lines. The coefficient of expansion per unit length per degree Centigrade, in the specimen tested by the United States Geological Survey, varied from 0.000,000,37 to 0.000,000,44 as compared with 0.000,011,4 for a steel tape of similar use. See GEODESY.

Bibliography. Consult: C. E. Guillaume, Recherches sur le nickel et ses alliages (Paris, 1898); id., Les applications des aciers au nickel (ib., 1904); O. B. French, "Six Primary Bases Measured with Steel and Invar Tapes," in United States Coast and Geodetic Survey, Report for 1907, Appendix No. 4 (Washington, 1908).

INVA'RIABLE PLANE. In the solar system, a plane about which the planets' orbits perpetually oscillate, deviating from it only to a very small extent on either side. This plane passes through the centre of gravity of the solar system and is so situated that if all the planets be projected on it, and if the mass of each planet be multiplied into the area which is described by the planet's projected radius vector in any assumed unit of time, the sum of such products will be a maximum. The most recent determination of the position of the invariable plane is that of See, who finds that the inclination to the ecliptic, and the longitude of the ascending node, are 1.5855° and 106.1463° (epoch 1850), respectively. Such a plane is not peculiar to the solar system, but must exist in all systems where the bodies are acted on by their mutual attractio. only. Consult Grant, History of Physical Astronomy (London, 1852). INVA'RIANT. See FORMS.

INVAR TAPES AND WIRES. See GEODESY; INVAR.

INVAʼSION (Lat. invasio, attack, from invadere, to invade, from in, in + vadere, to go, connected with OHG. watan, Ger. waten, AS. wadan, Eng. wade). The act of entry into an enemy's territory as an act of war. In ancient and mediæval times, when an army invaded a country, pillage, devastation, and slaughter were the rule. It was not until the War of the Spanish Succession that Marlborough and Villars, by a system of contribution, introduced comparative humanity into the conduct of armies. The Prussians and Austrians during the wars of Frederick the Great were generally dependent upon regularly levied supplies. During

the Revolutionary War the British government declared it to be a right of war: (1) to demand provisions and raise contributions, enforceable, if necessary, by the sword; (2) to ravage territory where there was no other way to bring an enemy to engagement or terms; (3) to treat all rebels as enemies. The right to ravage has not been asserted or acted upon since by either country, except in the case of the burning of the capitol and other buildings at Washington by the British in 1814, which was an unjustifiable violation of the laws of war. Napoleon enforced the principle that war must pay for war, and after the battle of Jena the exaction required of Prussia was more than 100,000,000 francs. The levy of 5,000,000,000 francs on France by Prussia at the end of the Franco-Prussian War in 1870 was the price paid to the invaders. The violation of the neutrality of Belgium by Germany in 1914 (see WAR IN EUROPE) aroused the strongest indignation all over the world and led to the entrance of Great Britain into the conflict.

The rights of an invader in the country occupied by him are important, but these rights of belligerent occupation, which are confined to the districts actually dominated by the invading force, must be carefully distinguished from those of conquest. The invaders' military rule in general supersedes the civil authority. In relation to property a sharp distinction must be drawn between public and private property. As to the former also the invader's rights are held to differ with its character. Thus the contents of the Palatine libraries were carried off to Rome during the Thirty Years' War, and Napoleon filled the Louvre galleries from every capital of Europe; but the rule is now well established that public money, military stores, and public buildings are lawful sources of plunder; public estates may be occupied, and the rents and profits therefrom appropriated; telegraph and railway property pressed into service, and public edifices interfering with military operations destroyed; but property not contributing to the uses of war must remain intact. The removal by the Germans of the astronomical instruments from the Observatory of Peking during the recent expedition of the allics against the Chinese capital was a violation of this rule.

The attitude of an invader towards private persons and property has been clearly defined by international law. Pillage is strictly forbidden. Private persons taking no part in the conflict are to remain unmolested, but inhabitants of an invaded district aiding their country forfeit protection and are subject to military execution, though the interests of humanity are conserved by this distinction between soldier and noncombatant. Property movable and immovable is to remain uninjured. If needed by the hostile army, the invading general may require its sale at prices fixed by himself, or even on occasions require their contribution without payment; but marauding must be checked by discipline and penalties. Such forced contributions of food, forage, labor, wagons, railroad rolling stock, or other means of transportation are called requisitions. See CONTRIBUTION; CONQUEST; and also INTERNATIONAL LAW and the authorities there referred to.

INVEC TA ET ILLA'TA (Lat. nom. pl., carried in and borne in). An expression of the civil law, found also in the law of Scotland, to denote all things which a tenant has brought

upon the premises, as his household furniture, tools, utensils, etc., and which are subject to the lien, or tacit mortgage, of the landlord for the rent of the premises. The English and American legal system in general recognizes no such lien, the landlord's remedies being confined to distress (q.v.) and to an action at law for the rent due.

INVECTED (from Lat. invectus, p.p. of invehere, to carry in, from in, in + vehere, to carry). In heraldry (q.v.), a partition line the reverse of engrailed.

INVENTION (Lat. inventio, finding out, from invenire, to find, from in, in + venire, to come). Literally, the act of making something not before made; also, the new thing produced. In patent law the term "invention" is specifically applied to any new and useful art, machine, manufacture, or composition of matter, or any new and useful improvement thereof, which when invented may under certain conditions be made the subject of the rights of a letter patent. In Great Britain the patent law expressly restricts such inventions to a "new manufacture," but the courts have construed this term so that it includes the four classes of inventions above named. Although it has been held that in the patent law "discovery" and "invention" are synonymous, in popular language and generally in legal literature the term "invention" has come to be used to designate a "patentable" invention or one that is "new" and useful.

To constitute an invention in this sense there must be a creating or origination of some useful thing that did not exist before, by means of an operation of the intellect. The extent of research and the simplicity or complexity of the result are of no importance, if the invention be new and useful and be something more than a construction following the beaten track of mechanical experience. Neither is any distinction made as to degree of usefulness or the amount of mechanical skill involved in the construction or making of the invention, so long as the usefulness or skill be not so slight as to make it negligible. It is no objection that the inventor was aided or assisted by ideas derived from others, so long as the final concrete product be something more and distinct from any one or all of these ideas or suggestions. The difficulty in drawing the line as to what is and what is not an invention is great. Mere simplicity is no objection and, indeed, may constitute the real excellence and newness of the invention. Neither is the use or application of old devices or machines an objection, for most patents are issued upon inventions based partly upon preexisting inventions. A mere advance or extended application of an original invention, changed only in degree and doing substantially the same thing in the same way by the same means, but with better results, is not an invention. There must be a new idea grafted upon the old invention. By reason of the difficulty here referred to the law is liberally applied to protect everything that might be properly called new and useful. See PATENT, and consult the authorities there referred to.

INVENTION. A musical term applied by J. S. Bach to a collection of 15 short piano pieces for two voices. In the very verbose title of the original edition Bach explains that he uses the term in the sense of "musical idea" or "theme," and that the object of the pieces is to show a proper development after the theme has once

been "invented." The term has never been used by any other composer, nor again by Bach himself, who gave to a collection of 15 other pieces, identical in character and development, but for three voices, the title Sinfonien.

INVENTION OF THE CROSS. See CROSS, INVENTION OF THE.

IN'VENTORY (from Lat. inventarium, list, from Lat. invenire, to find, from in, in + venire, to come; connected with Gk. Baíveir, bainein, Skt. gam, to go, and ultimately with Eng. come). A written instrument setting forth in the form of a systematic schedule all the goods, chattels, and other personal property of a person or estate, whether for use in a legal proceeding or for ordinary commercial purposes. The term and the legal practice connected with its use originated in the reform of the Roman law instituted by Justinian to relieve the heir of a deceased person from his personal liability. In order to relieve the heir, and at the same time to protect creditors and legatees, a law was enacted under which the heir was relieved of all liability for the debts and legacies of his ancestor, excepting in so far as the property inherited by him would enable him to discharge the same, provided that within a certain time he should duly prepare and file a written instrument containing a correct enumeration of all property, real and personal, left by the deceased. See HEIR.

Until about two centuries after the Norman Conquest the identification of heir and ancestor was as complete under the English law as it had been under the Roman. About that time, partly through the influence of the Roman law, the heir's liability was limited to the amount of property descending to him; executors or administrators superseded him for the purpose of administration of his ancestor's personal estate, and the Roman practice of making an inventory of the assets of the estate was introduced. This plan was probably adopted more for the practical advantage of compelling the personal representatives of the deceased to commit themselves at the outset as to the amount and character of property coming into their hands, than as a means of relieving the heir from liability, as that reform had apparently already been accomplished. The ecclesiastical courts assumed jurisdiction of estates, and inventories of the personal property were required to be filed in these courts, where they were open to the inspection of all persons interested therein. This practice is substantially followed to-day. The inventory usually contains a list of all the personal property of the decedent, with the appraised value set opposite each item, as well as a schedule of his debts and liabilities, the executor or administrator certifying by oath or affirmation that the whole is true to the best of his knowledge and belief. It is filed in the court having jurisdiction of decedents' estates and may be examined by the heirs, next of kin, legatees, and creditors of the deceased, who may object to it if anything is omitted or improperly entered. After the inventory is filed, the execu tor or administrator becomes accountable for the disposition or distribution of every item set forth therein, and it is therefore a most efficient means of insuring the honest administration of estates.

The term "inventory" is also properly employed to designate the lists of assets prepared by the trustees of bankrupts' or insolvents' es

tates, and by guardians of infants or other legally incompetent persons, for the information of the court having jurisdiction over them and for the more convenient discharge of their fiduciary duties. See ESTATE; EXECUTOR.

IN VERA'RAY. A royal and municipal borough, the county town of Argyllshire, Scotland, at the mouth of the Aray in Loch Fyne, 45 miles northwest of Glasgow (Map: Scotland, C 3). An obelisk commemorates the death of 17 Campbells, who were hanged here without trial, in 1685, for their adherence to Presbyterianism. Inveraray Castle, the seat of the dukes of Argyll, is close to the town. Fishing for herring is the chief occupation. Pop., 1901, 678; 1911, 533.

IN'VERCARGILL. The capital of the County of Southland, South Island, New Zealand, on an estuary called the New River Harbour, 17 miles from its port at the Bluff (Map: New Zealand, South I., B 7). New River Harbour at the town takes vessels drawing 10 feet. The Bluff has a good harbor, with wharfage for vessels of any tonnage, and is a port of call for the Melbourne and New Zealand mail steamers. The Bluff is 150 miles southwest of Dunedin, with which it is connected by rail. Its industries include numerous woolen mills, saw mills, flour mills, breweries, and meat-refrigerating establishments. It is the centre of a large agricultural and cattle-raising country, and a large export trade has grown up in wool, timber, and grain. The town is well built on a rectangular plan, has government buildings and a hospital. It is lighted by gas and has street tramways. The first settlement of Invercargill was begun in 1857. Pop., 1901, 9950; 1911, 12,782, (with suburbs) 15,858.

INVERLOCHY, în'věr-lõK'ê. A castle in Inverness-shire, near which, on Feb. 2, 1645, an army of about 2000 under Sir Duncan Campbell was routed and for the most part cut to pieces by an army numbering scarcely 1500 under the Marquis of Montrose (q.v.). The castle is now in ruins. Consult Gardiner, History of the Great Civil War, vol. ii (London, 1886-91). See GRAHAM, JAMES.

IN VERNESS'. A town in Inverness Co., Cape Breton Island, Nova Scotia, Canada, situated on Big River and on the line of the Inverness Railway and Coal Company, about 150 miles by rail from Sydney and 61 miles by rail from Point Tupper. The colliery of the Inverness Railway and Coal Company is situated here. Copper, gypsum, and fire clay are found in the vicinity. Pop., 1911, 2719.

INVERNESS. A royal, parliamentary, and municipal burgh and seaport, the county town of Inverness-shire, Scotland, on both banks of the Ness, near its embouchure in the Moray Firth, 118 miles north of Perth. The Caledonian Canal empties into the Ness at Inverness (Map: Scotland, D 2). The town, picturesquely surrounded by wooded hills, has handsome wide streets and many beautiful residences. Its principal buildings are St. Andrews Episcopal Cathedral, the county hall, public library, observatory, infirmary, lunatic asylum, and Royal Academy. Other features are the fountain, containing the famous blach-na-cudain, long regarded as the town palladium; the suspension bridge, and the Islands promenade. It has a high school, a school of science and art, and an institute for the blind. There are iron foundries, shipbuilding yards, woolen manufactures, dis

tilleries, tanneries, soap and candle factories, nurseries, saw mills, granite works, railway shops, breweries, and thread-making and bleaching works. The harbor, docks, and roads afford good accommodations, and a considerable trade is carried on. The town owns its own gas works. Inverness is of great antiquity, having been one of the Pictish capitals. William the Lion gave it four charters and made it a royal burgh. In 1411 it was burned by Donald of the Isles. The old castle where Macbeth murdered Duncan was razed by Malcolm Canmore, who replaced it by another which was destroyed by Prince Charles Stuart in 1746. The remains exist at the north of the town of the citadel which was built by Cromwell in 1652, and which was demolished at the Restoration. Pop., 1901, 23,075; 1911, 22,216. Consult: Mackintosh, Invernessiana (Inverness, 1875); Anderson, Inverness before Railways (ib., 1885); Grant, The Commissariat Record of Inverness (Edinburgh, 1897).

INVERNESS-SHIRE.

The largest county

of Scotland, in the northwest division (Map: Scotland, D 2). It includes several of the western islands, viz., Skye, Harris, North and South Uist, Barra, etc., and is bounded east by the counties of Aberdeen, Banff, Elgin, and Nairn; south by Perth and Argyllshire; west by the Atlantic Ocean; and north by Ross-shire and Cromarty. Area, 4211 square miles, most of which, except the valley of the Ness, is barren heath. The county consists chiefly of deer forests, which are rented as hunting ranges. It has valuable coast fisheries. Inverness, the county seat, is the only town. Pop., 1901, 90,104; 1911, 87,270. Consult J. C. Lees, History of the County of Inverness (Edinburgh, 1897), and Records, edited by Mackay and Boyd, vol. i (Aberdeen, 1911).

INVER'SION (Lat. inversio, from invertere, to turn about, from in, invertere, to turn). In music this term is applied to intervals, chords, and phrases or passages. An interval is said to be inverted where the position of its two notes is reversed by transposing one of them an octave higher or lower. The inversion changes the name and to some extent the character of the interval. The name or number of an inverted interval will be found by subtracting its original number from nine. Thus, a unison inverted becomes an octave, a second becomes a seventh, a third becomes a sixth, and so on, as shown in the following table of inversions:

which it hydrolyzes, forming grape sugar (glucose) and fruit sugar (fructose). Invertase acts most rapidly at 50° to 60° C. in a slightly acid medium. It can break up practically unlimited quantities of the sugar without being itself materially diminished. Invertase occurs in many fungi and in some bacteria; more recently it has been found widely distributed in the seed plants, in whose nutritive work it plays an important part, because cane sugar is probably one of the most widely distributed foods in the higher plants. Invertase is secreted abundantly by yeast, and without it yeast is unable to ferment cane sugar. After inversion of cane sugar the products are broken up by the enzyme zymase (q.v.). See ENZYME; FER

MENTATION.

INVERTEBRATA (Neo-Lat. nom. pl., from Lat. in-, not + vertebratus, vertebrate, from vertebra, joint, from vertere, Skt. vart, OChurch Slav. vrutēti, to turn, Goth. wairpan, AS. weorpan, OHG. werdan, Ger. werden, to become). Animals which do not have a vertebral column or spine. The term is used in contrast with Vertebrata (q.v.), or animals with a backbone. One group, then, is formed on positive and the other on negative characters. Before the anatomical structure and the embryological development of animals was very generally worked out, the barrier between invertebrates and vertebrates was supposed to be absolute; but with the refinement of anatomical and embryological methods of study, brought about in a great measure by the use of the microscope, the hiatus between them is nearly bridged over. Ascidians

are now considered to be degenerate ancestors of vertebrates; some of the nemertean and chatopod worms approach vertebrates in certain characters, and Balanoglossus and Cephalodiscus (q.v.) are frequently called hemichordata (see ADELOCHORDA), because they are so near the boundary line between vertebrates and invertebrates that they can be said to be only half vertebrates. And not only has this barrier been broken down, but, with our increased knowledge, the absolute independence and isolation of many different groups of invertebrate animals which the earlier systematists believed to exist must be abandoned. The foundation of the zoology of these animals, as there defined, was laid by Lamarck (q.v.) in a monumental work, Système des animaux sans vertèbres, published in Paris in 1801; followed in 1815-22 by his Histoire naturelle des animaux sans vertèbres.

Unison. 8v.

2d.

7th. 3d. 6th. 4th. 5th. By inversion major intervals become minor, and minor become major; diminished intervals become augmented, and augmented become diminished. But the two perfect intervals of the fourth and the fifth remain perfect when inverted. In these examples the transposed note is placed an octave higher, but naturally the same result is arrived at by transposing it downward, as will be seen by reading the table backward. For inversion of chords, see HARMONY, Chords. For inversion of phrases or passages, see COUNTERPOINT.

INVERSION, IN MATHEMATICS. See CIRCLE. INVERT'ASE (from invert). One of the enzymes (see ENZYME) which acts upon certain sugars, especially upon cane sugar (saccharose),

Bibliography. Von Siebold, Anatomy of the Invertebrata (Boston, 1874); Shipley, Zoology of the Invertebrates (London, 1893); Bumpus, Laboratory Course in Invertebrate Zoology (2d ed., New York, 1893); McMurrich, Textbook of Invertebrate Morphology (ib., 1894); Brooks, Handbook of Invertebrate Zoology (Boston, 1897); Böhmig, Die wirbellosen Tiere, vols. i-ii (Leipzig, 1909-11); Lang, Handbuch der Morphologie der wirbellosen Tiere, vols. i-iv (Jena, 1912-13); Rosalie Lulham, Introduction to Zoology with Directions for Practical Work (Invertebrates) (New York, 1913); G. A. Drew, Laboratory Manual of Invertebrate Zoology (2d ed., Philadelphia, 1913).

INVESTITURE (Lat. investitura, from in

vestire, to invest, from in, in + vestire, to clothe, from vestis, garment; connected with Gk. évvúval, hennynai, Skt. vas, Goth. wasjan, OHG., AS. werian, Eng. wear). In feudal and ecclesiastical history, the act of giving corporal possession of a manor, office, or benefice, accompanied by a certain ceremonial, such as the delivery of a branch, a banner, or an instrument of office, more or less designed to signify the power or authority which it was supposed to convey. The chief interest is in ecclesiastical investitures, and the contest which arose concerning them is so interwoven with the whole course of medieval history that a brief account of its nature and origin is indispensable to a right understanding of many of the most important events of that period. The system of feudal tenure had become so universal that it affected even the land held by ecclesiastics, and attached to most of the higher ecclesiastical dignities, monastic as well as secular. Accordingly ecclesiastics who, in virtue of the ecclesiastical office which they held, came into possession of the lands attached to such offices, were regarded as becoming by the very fact feudatory to the suzerain of these lands; and, as a not unnatural result, the suzerains thought themselves entitled to claim, in reference to these personages, the same rights which they enjoyed over the other feudatories of their domains. Among these rights was that of granting solemn investiture. In the case of bishops, abbots, and other Church dignitaries, the form of investiture consisted in the delivery of a pastoral staff or crosier, and the placing of a ring upon the finger; and as these badges of office were emblematic-the one of spiritual care of souls, the other of the espousals, as it were, between the pastor and his church or monastery-the possession of this right by the lay princes, which they had held since the time of Charles the Great, became in the latter part of the eleventh century a source of disquietude to the Church. On the part of the suzerains it was maintained that they did not claim to grant by this rite the spiritual powers of the office, their functions being solely to grant possession of its temporalities, and of the rank thereto annexed. But the Church party urged that the ceremonial involved the granting of spiritual powers; insomuch that, in order to prevent the clergy from electing to a see when vacant, it was the practice of the emperors to take possession of the crosier and ring until it should be their own pleasure to grant investiture to their favorites. The investiture strife was complicated by the rebellions of the nobles in Germany; by the strife between rival parties in the Lombard cities; by the conflict of parties in Rome; and specifically by the question of the property of Countess Matilda of Tuscany. (See MATILDA; GERMANY; HENRY IV.) The disfavor in which the practice of investiture was held by the clergy found its most energetic expression in the person of Pope Gregory VII, who, having in the year 1074 enacted most stringent measures for the repression of simony, proceeded in 1075 to condemn, under excommunication, the practice of lay investitures, as almost necessarily connected with simony or leading to it. This prohibition, however, only regarded investiture in the objectionable form in which it was then practiced, or investiture of whatever form, when the office had been obtained simoniacally. But other members of the clergy went much further, and a pope of the same century, Urban II

(1095), absolutely and entirely forbade, not alone lay investiture, but the taking of an oath of fealty to a lay suzerain by an ecclesiastic, even though holding lands of him by the ordinary feudal tenure. The contest lasted from 1075 to 1122. In the beginning of the twelfth century it assumed a new form, when Pope Paschal II actually agreed, in 1111, to surrender all the possessions with which the Church had been endowed, and which alone formed the pretext of the claim to investiture on the part of the Emperor, on condition that the Emperor Henry V give up that claim to investiture. This, however, never had any practical effect; but, the other subjects of contention being removed, the contest was finally adjusted by the celebrated Concordat of Worms in 1122, by the terms of which the Emperor agreed to give up the form of investiture with the ring and pastoral staff, to grant to the clergy the right of free elections, and to restore all the possessions of the Church of Rome which had been seized either by himself or by his father; while the Pope, on his part, consented that the election should be held in the presence of the Emperor or his representative; that investiture might be given by the Emperor, but only by the touch of the sceptre; and that the bishops and other Church dignitaries should faithfully discharge all the feudal duties which belonged to their fief.

For the investiture troubles in Germany, consult Mirbt, Die Publizistik im Zeitalter Gregors VII. (Leipzig, 1894); in England, Böhmer, Kirche und Staat in England und in der Normandie im XI. und XII. Jahrhundert (ib., 1899); for those in France, Ibach, Der Kampf zwischen Papsttum und Königtum von Gregor VII. bis Calixtus II. (Frankfort, 1884), and Imbart de la Tour, Les élections épiscopales dans l'église de France du IXème au XIIème siècle (Paris, 1891).

INVINCIBLE ARMA'DA. See ARMADA. INVINCIBLE DOCTOR, THE (Lat. Invincibilis Doctor). A name given to the English theologian William of Occam, on account of his logical methods of argument.

INVINCIBLES (Lat. invincibilis, unconquerable, from in-, not + vincibilis, conquerable, from vincere, to conquer). Members of a secret Irish society composed of some of the most desperate spirits of the Fenian association. Each member was acquainted by name with but two othersthe one who nominated him to membership and the one whom he in turn nominated. The chief was a mysterious person known simply as No. 1. The object of the society was the assassination of officials, and to its members was charged the murder of Lord Frederick Cavendish, the newly appointed Irish Secretary, and T. H. Burke, the Undersecretary, in Phoenix Park, Dublin, on May 6, 1882. Consult Annual Register (London, 1883, 1890). See FENIAN SOCIETY.

INVI'OLABILITY (Lat. inviolabilitas, from inviolabilis, inviolable, from in-, not + violabilis, violable, from violare, to violate, from vis, Gk. is, is, strength, violence). In international law, the freedom or immunity which attaches to a greater or less degree to the public vessels and their crews and to the diplomatic agents of one country when within the territory of another state, and also in a very limited degree to merchant vessels in foreign waters. This immunity is extended upon the fiction of exterritoriality (q.v.). With respect to public vessels it does not allow the granting of asylum (q.v.) to