OSAKA, or OzAKA, a city of Japan in the province of Settsu. Pop. (1908) 1,226,590. It lies in a plain bounded, except westward, where it opens on Osaka Bay, by hills of considerable height, on both sides of the Yodogawa, or rather its headwater the Aji (the outlet of Lake Biwa), and is so intersected by riverbranches and canals as to suggest a comparison with a Dutch town. Steamers ply between Osaka and Kobe-Hiogo or Kobe, and Osaka is an important railway centre. The opening of the railway (1873) drew foreign trade to Kobe, but a harbour for ocean-steamers has been constructed at Osaka. The houses are mainly built of wood, and on the 31st of July 1909 some 12,000 houses and other buildings were destroyed by fire. Shin-sai Bashi Suji, the principal thoroughfare, leads from Kitahama, the district lying on the south side of the Tosabori, to the iron suspension bridge (Shin-sai Bashi) over the Dotom-bori. The foreign settlement is at Kawaguchi at the junction of the Shirinashi and the Aji. It is the seat of a number of European mission stations. Buddhist and Shinto temples are numerous. The principal secular buildings are the castle, the mint and the arsenal. The castle was founded in 1583 by Hideyoshi; the enclosed palace, probably the finest building in Japan, survived the capture of the castle by Iyeyasu (1615), and in 1867 and 1868 witnessed the reception of the foreign legations by the Tokugawa shoguns; but in the latter year it was fired by the Tokugawa party. It now provides military headquarters, containing a garrison and an arsenal. The whole castle is protected by high and massive walls and broad moats. Huge blocks of granite measuring 40 ft. by 10 ft. or more occur in the masonry. The mint, erected and organized by Europeans, was opened in 1871. Osaka possesses iron-works, sugar refineries, cotton spinning mills, ship-yards and a great variety of other manufactures. The trade shows an increase commensurate with that of the population, which in 1877 was only 284,105.

Osaka owes its origin to Rennio Shonin, the eighth head of the Shin-Shu sect, who in 1495-1496 built, on the site now occupied by the castle, a temple which afterwards became the principal residence of his successors. In 1580, after ten years' successful defence of his position, Kenryo, the eleventh abbot," was obliged to surrender; and in 1583 the victorious Hideyoshi made Osaka his capital. The town was opened to foreign trade in 1868.

44

a new search expedition for Sir John Franklin, and in 1850 was appointed to the command of the steam-tender "Pioneer " in the Arctic expedition under Captain Austin, in the course of which he performed (1851) a remarkable sledge-journey to the western extremity of Prince of Wales Island. He published an account of this voyage, entitled Stray Leaves from an Arclic Journal (1852), and was promoted to the rank of commander shortly afterwards. In the new expedition (1852-1854) under Sir Edward Belcher he again took part as commander of the "Pioneer." In 1856 he published the journals of Captain Robert M'Clure, giving a narrative of the discovery of the North-West Passage. Early in 1855 he was called to active service in connexion with the Crimean War, and being promoted to post-rank in August of that year was appointed to the Medusa," in which he commanded the Sea of Azoff squadron until the conclusion of the war. For these services he received the C.B., the Cross of the Legion of Honour, and the Medjidie of the fourth class. As commander of the " Furious" he took a prominent part in the operations of the second Chinese War, and performed a piece of difficult and intricate navigation in taking his ship 600 m. up the Yangtse-kiang to Hankow (1858). He returned to England in broken health in 1859, and at this time contributed a number of articles on naval and Chinese topics to Blackwood's Magazine, and wrote The Career, Last Voyage and Fate of Sir John Franklin (1860). In 1861 he commanded the Donegal" in the Gulf of Mexico during the trouble there, and in 1862 undertook the command of a squadron fitted out by the Chinese government for the suppression of piracy on the coast of China; but owing to the non-fulfilment of the condition that he should receive orders from the imperial government only, he threw up the appointment. In 1864 he was appointed to the command of the "Royal Sovereign" in order to test the turret system of ship-building, to which this vessel had been adapted. In 1865 he became agent to the Great Indian Peninsula Railway Company, and two years later managing director of the Telegraph Construction and Maintenance Company. In 1873 he attained flag-rank. His interest in Arctic exploration had never ceased, and in 1873 he induced Commander Albert Markham to undertake a summer voyage for the purpose of testing the conditions of ice-navigation with the aid of steam, with the result that a new Arctic expedition, under Sir George Nares, was determined upon. He was a member of the committee which made the preparations for this expedition, and died a few days after it had sailed.

OSBORNE, a mansion and estate in the Isle of Wight, England, S.E. of the town of East. Cowes. The name of the manor in early times is quoted as Austerborne or Oysterborne, and the estate comprised about 2000 acres when, in 1845, it was purchased from Lady Isabella Blackford by Queen Victoria. The queen subsequently extended the estate to nearly 3000 acres, and a mansion, in simple Palladian style, was built from designs of Mr T. Cubitt. Here the queen died in 1901, and by a letter, dated Coronation Day 1902, King Edward VII. presented the property to the nation. By his desire part of the house was transformed into a convalescent home for officers of the navy, and army, opened in 1904.

OSAWATOMIE, a city of Miami county, Kansas, U.S.A., about 45 m. S. by W. of Kansas City, on the Missouri Pacific railway. Pop. (1900) 4191 (227 negroes); (1905, state census) 4857; (1910) 4046. A state hospital for the insane (1866) is about 1 m. N.E. of the city. The region is a good one for general farming, and natural gas and petroleum are found in abundance in the vicinity. Osawatomie was settled about 1854 by colonists sent by the Emigrant Aid Company, and was platted in 1855; its name was coined from parts of the words Osage" and "Pottawatomie." It was the scene of two of the battles " of the "Border War," and of much of the political violence resulting from the clashes between the "pro-slavery and the "" free-state factions of Missouri and Kansas. On the 7th of June 1856 it was plundered by about 170 pro-slavery men from Missouri. On the 30th of August 1856 General John W. Reid, commanding about 400 Missourians, attacked the town. The attack was resisted by Captain John Brown (who had come to Osawatomie in the autumn of 1855) at the head of about 40 men, who were soon overpowered. Of Captain Brown's men, four were killed and two were executed. The town was looted and practically destroyed. A park commemorating the battle was dedicated here on the 31st of August 1910. : OSBORN, SHERARD (1822-1875), English admiral and Arctic explorer, the son of an Indian army officer, was born on the 25th of April 1822. Entering the navy as a first-class volunteer in 1837, he was entrusted in 1838 with the command of a gunboat at the attack on Kedah in the Malay Peninsula, and was present at the reduction of Canton in 1841, and at the capture of the batteries of Woosung in 1842. From 1844 till 1848 he was gunnery OSCA LINGUA, or OSCAN, the name given by the Romans mate and lieutenant in the flag-ship of Sir George Seymour to the language of (1) the Samnite tribes, and (2) the inhabitants in the Pacific. He took a prominent part in 1849 in advocating | of Campania (excluding the Greek colonies) from the 4th century

In 1903 there was opened on the Osborne estate a Royal Naval College. The principal buildings lie near the Prince of Wales's Gate, the former royal stables being adapted to use as class-rooms, a mess-room, and other apartments, while certain adjacent buildings were also adapted, and a gymnasium and series of bungalows to serve as dormitories, each accommodating thirty boys, were erected, together with quarters for officers, and for an attached body of marines. By the river Medina, on the Kingsdown portion of the estate, a machine shop and facilities for boating are provided.

At the church of St Mildred, Whippingham, 1} m. S.S.E. of East Cowes, there are memorials to various members of the royal family.

5. Final & became o in both Oscan (u) and Umbrian (often written with the co- suffix and with the plebs of Rome (see VOLSCI), e.g. Oscan viù = Lat. uia; Umb. adro (nom. pl. neut.) = Lat. atra.

For further evidence as to the history of the names Osci, Opsci, (although the misleading symbol with an accent upon it is fre Opici, see R. S. Conway, The Italic Dialects, p 149.

OSCAR I. (1799-1859), king of Sweden and Norway, was the son of General Bernadotte, afterwards King Charles XIV. of Sweden, and his wife, Eugénie Désirée Clary, afterwards Queen | Desideria. When, in August 1810, Bernadotte was elected crown prince of Sweden, Oscar and his mother removed from Paris to Stockholm (June 1811). From Charles XIII. the lad received the title of duke of Södermanland (Sudermania). He quickly acquired the Swedish language, and, by the time he reached manhood, had become a general favourite. His very considerable native talents were developed by an excellent education, and he soon came to be regarded as an authority on all social-political questions. In 1839 he wrote a series of articles on popular education, and (in 1841) an anonymous work, Om Straff och straffanstalter, advocating prison reforms. during his father's lifetime he was viceroy of Norway. On the Twice 19th of June 1823 he married the princess Josephine, daughter of Eugène de Beauharnais, duke of Leuchtenberg, and granddaughter of the empress Josephine. In 1838 the king began to suspect his heir of plotting with the Liberal party to bring about a change of ministry, or even his own abdication. If Oscar did not actively assist the Opposition on this occasion, his disapprobation of his father's despotic behaviour was notorious, though he avoided an actual rupture. Yet his liberalism was of the most cautious and moderate character, as the Opposition, shortly after his accession (March 8th, 1844), discovered to their great chagrin. He would not hear of any radical reform of the cumbrous and obsolete constitution. But one of his earliest measures was to establish freedom of the press. Most of the legislation during Oscar I.'s reign aimed at improving the economic position of Sweden, and the riksdag, in its address to him in 1857, rightly declared that he had promoted the material prosperity of the kingdom more than any of his predecessors. In foreign affairs Oscar I. was a friend of the principle of nationality. In 1848 he supported Denmark against Germany; placed Swedish and Norwegian troops in cantonments in Fünen and North Schleswig (1849-1850); and mediated the truce of Malmö (August 26th, 1848). He was also one of the guarantors of the integrity of Denmark (London protocol, May 8th, 1852). As early as 1850 Oscar I. had conceived the plan of a dynastic union of the three northern kingdoms, but such difficulties presented themselves that the scheme had to be abandoned. He succeeded, however, in reversing his father's obsequious policy towards Russia. His fear lest Russia should demand a stretch of coast along the Varanger Fjord induced him to remain neutral during the Crimean War, and, subsequently, to conclude an alliance with Great Britain and France (November 25th, 1855) for preserving the territorial integrity of Scandinavia. Oscar 1. left four sons, of whom two, Carl (Charles XV.) and Oskar Fredrik (Oscar II.), succeeded to his throne.

of circumstance, the genitive in judicial phrases, the use of the neut. | sity of Upsala, where he distinguished himself in mathematics. adj. as an abstract substantive, e.g. Oscan ualaemom toulicom," opti. In 1857 he married Princess Sophia Wilhelmina, youngest mum publicum," 1.e." optima rei publicae ratio." In verbal forms the same use of the gerundive combined with the noun to represent daughter of Duke William of Nassau. He succeeded his brother the total verbal action, e.g. Umb. ocrer pehaner paca, "arcis piandae Charles XV. on the 18th of September 1872, and was crowned causa"; the usual sequence of tenses, e.g. the imperfect subj in in the Norwegian cathedral of Drontheim on the 18th of July Oratio Obliqua representing the fut. indic. in Oratio Recta (see 1873. At his accession he adopted as his motto Brödrafolkens Cippus Abellamus b 23, 25); and finally the use of the perf. sub). Val, "the welfare of the brother folk," and from the first he in Oscan in prohibitions (nep fefacid, positive commands (Osc. sakrafir, see above). neue fecerit "), but also in Fuller accounts of the dialects in all these aspects will be found between Sweden and Norway. The political events which led realized the essential difficulties in the maintenance of the union most exhaustively in Von Planta, Grammatik der Oskisch-umbrischen Dialekte (Strassburg, 1892-1897). Less fully, but very clearly and acutely in C. D. Buck's Oscan and Umbrian Grammar (Boston, up to the final crisis in 1905, by which the thrones were separated, U.S.A., 1904). R. S. Conway, The Italc Dialects, vol. ii. (Cambridge, SWEDEN. But it may be said that the peaceful solution eventu are dealt with in the historical articles under NORWAY and 1897), gives a fuller account of the alphabets and their history, a ally adopted could hardly have been attained but for the tact Conspectus of the Accidence and an account of the Syntax at some length. (R. S. C.) and patience of the king himself. He declined, indeed, to permit relations between the two countries were restored before his any prince of his house to become king of Norway, but better death, which took place at Stockholm on the 8th of December 1907. His acute intelligence and his aloofness from the dynastic considerations affecting most European sovereigns gave the king considerable weight as an arbitrator in international questions. At the request of Great Britain, Germany and the United States in 1889 he appointed the chief justice of Samoa, and he was again called in to arbitrate in Samoan affairs in 1899. In 1897 he was empowered to appoint a fifth arbitrator if necessary in the Venezuelan dispute, and he was called in to act as quashed by the senate. He won many friends in England by umpire in the Anglo-American arbitration treaty that was his outspoken and generous support of Great Britain at the time in The Times of the 2nd of May 1900, when continental opinion of the Boer War (1899-1902), expressed in a declaration printed was almost universally hostile.

See T. Almén, Atten Bernadotte (Stockholm, 1896); and C. E. Akrell, Minnen från Carls XIV, Oscars I. och Carls XV. Lagar (Stockholm, 1884, 1885). Also NORWAY (history) and SWEDEN (history).

OSCAR II. (1829-1907), king of Sweden and Norway, son of Oscar I., was born at Stockholm on the 21st of January 1829. He entered the navy at the age of eleven, and was appointed junior lieutenant in July 1845. Later he studied at the univer

Himself a distinguished writer and musical amateur, King
encourage
Oscar proved a generous friend of learning, and did much to
dominions. In 1858 a collection of his lyrical and narrative
the development of education throughout his
poems, Memorials of the Swedish Fleet, published anonymously,
obtained the second prize of the Swedish Academy. His "Con-
tributions to the Military History of Sweden in the Years 1711,
1712, 1713," originally appeared in the Annals of the Academy,
and were printed separately in 1865. His works, which in-
cluded his speeches, translations of Herder's Cid and Goethe's
Torquato Tasso, and a play, Castle Cronberg, were collected in
appeared in 1885-1888. His Easter hymn and some other
two volumes in 1875-1876, and a larger edition, in three volumes,
of his poems are familiar throughout the Scandinavian countries.
His Memoirs of Charles XII. were translated into English in
1879. In 1885 he published his Address to the Academy of Music,
and a translation of one of his essays on music appeared in
Literature on the 19th of May 1900. He had a valuable collection
of printed and MS. music, which was readily accessible to the
historical student of music.

(b. 1858), succeeded him as Gustavus V. His second son, Oscar
His eldest son, Oscar Gustavus Adolphus, duke of Wärmland
(b. 1859), resigned his royal rights on his marriage in 1888
with a lady-in-waiting, Fröken Ebba Munck, when he assumed
the title of Prince Bernadotte. From 1892 he was known as
Count Wisborg. The king's other sons were Charles, duke of
Westergötland (b. 1861), who married Princess Ingeborg of
Denmark; and Eugène, duke of Nerike (b. 1865), well known
as an artist.
on of antiemet ;I

meaning black drink) (c. 1804-1838), a Seminole American
OSCEOLA (a corruption of the Seminole As-se-he-ho-lar,
Indian, leader in the second Seminole War, was born in Georgia,
near the Chattahoochee river. His father was an Englishman
or Mikasuki division. In 1808 he removed with his mother
named William Powell; his mother a Creek of the Red Stick
into northern Florida. When the United States commissioners
Landing (9th of May 1832) and Fort Gibson (28th of March
negotiated with the Seminole chiefs the treaties of Payne's
1833) for the removal of the Seminoles to Arkansas, Osceola
seized the opportunity to lead the opposition of the young
warriors, and declared to the U.S. agent, General Wiley Thoinp-

The festivals at which the hanging of oscilla took place were: (1) The Sementivae Feriae, or sowing festivals, and the Paganalia, the country festivals of the tutelary deities of the pagi; both took place in January. Here the oscilla were hung on trees, such as the vine and the olive, oak and the pine, and represented the faces of Liber, Bacchus or other deity connected with the cultivation of the soil (Virg. Georg. ii. 382-396). (2) The Feriae Latinae; in this case games were played, among them swinging (oscillatio); cf. the Greek festival of Acora (see ERIGONE). Festus (s.v. Oscillum, ed. Müller, p. 194) says that this swinging was called oscillatio because the swingers masked their faces (os celare) out of shame. (3) At the Compitalia, Festus says (Paul. ex Fest, ed. Müller, p. 239) that pilae and effigies viriles et muliebres made of wool were hung at the crossof the family, the effigies that of the children; the purpose being roads to the Lares, the number of pilae equalling that of the slaves to induce the Lares to spare the living, and to be content with the pilae and images. This has led to the generally accepted conclusion that the custom of hanging these oscilla represents an older practice of expiating human sacrifice. There is also no doubt a connexion with lustration by the purifying with air.

son, that any chief who prepared to remove would be killed. | in English "oscillation," the act of swinging backwards and At the Agency (Fort King, in Marion county) he became more forwards, periodic motion to and fro, hence any variation or violent, and in the summer of 1835 Thompson put him in irons. fluctuation, actual or figurative. For the scientific problems From this confinement he obtained his release by a profession connected with oscillation see MECHANICS and OSCILLOGRAPH. of penitence and of willingness to emigrate. Late in November Many oscilla or masks, representing the head of Bacchus 1835 he murdered Charley Emathla (or Emartla), a chief who or of different rustic deities, are still preserved. There is a marble was preparing to emigrate with his people, and on the 28th of oscillum of Bacchus in the British Museum. Others still in December he and a few companions shot and killed General existence are made of earthenware, but it seems probable that Thompson. On the same day two companies of infantry under wax and wood were the ordinary materials. Small rudely shaped Major Francis L. Dade were massacred at the Wahoo Swamp figures of wool, known as pilae, were also hung up in the same near the Withlacoochee river, while marching from Fort Brooke way as the oscilla. on Tampa Bay to the relief of Fort King. In a battle fought three days later at a ford of the Withlacoochee, Osceola was at the head of a negro detachment, and although the Indians and negroes were repulsed by troops under General Duncan L. Clinch (1787-1849), they continued, with Osceola as their most crafty and determined leader, to murder and devastate, and Occasionally to engage the troops. In February 1836 General Edmund P. Gaines (1777-1849), with about 1100 men from New Orleans, marched from Fort Brooke to Fort King. When he attempted to return to Fort Brooke, because there were not the necessary provisions at Fort King, the Indians disputed his passage across the Withlacoochee. In the same year Generals Winfield Scott and Richard K. Call (1791-1862) conducted campaigns against them with little effect, and the year closed with General Thomas Sidney Jesup (1788-1860) in command with 8000 troops at his disposal. With mounted troops General Jesup drove the enemy from the Withlacoochee country and was pursuing them southward toward the Everglades when several chiefs expressed a readiness to treat for peace. In a conference at Fort Dade on the Withlacoochee on the 6th of March 1837 they agreed to cease hostilities, to withdraw south of the Hillsborough river, and to prepare for emigration to Arkansas, and gave hostages to bind them to their agreement. But on the 2nd of June Osceola came to the camp at the head of about 200 Mikasuki (Miccosukees) and effected the flight of all the Indians there, about 700 including the hostages, to the Everglades. Hostilities were then resumed, but in September Brigadier General Joseph M. Hernandez captured several chiefs, and a few days later there came from Osceola a request for an interview. This was granted, and by command of General Jesup he was taken captive at a given signal and carried to Fort Moultrie, at Charleston, South Carolina, where he died in January 1838. The war continued until 1842, but after Osceola's death the Indians sought to avoid battle with the regular troops and did little but attack the unarmed inhabitants. See J. T. Sprague, The Origin, Progress and Conclusion of the Florida War (New York, 1848).

OSCHATZ, a town in the kingdom of Saxony, in the valley of the Döllnitz, 36 m. N.W. of Dresden, on the trunk railway to Leipzig. Pop. (1905) 10,854. One of its three Evangelical churches is the handsome Gothic church of St Aegidius, with twin spires. Sugar, felt, woollens, cloth and leather are manufactured, and there is considerable trade in agricultural produce. Four miles west lies the Kolmberg, the highest eminence in the north of Saxony.

See C. Hoffmann, Historische Beschreibung der Stadt Oschatz (Oschatz, 1873-1874); and Gurlitt, Bau- und Kunstdenkmäler der Amismannschaft Oschatz (Dresden, 1905).

OSCHERSLEBEN, a town of Germany, in the Prussian province of Saxony, on the Bode, 24 m. by rail S. W. of Magdeburg, and at the junction of lines to Halberstadt and Jerxheim. Pop. (1905) 13,271. Among its industrial establishments are sugar refineries, iron-foundries, breweries, machine-shops and brick. works. Oschersleben is first mentioned in 803, and belonged in the later middle ages to the bishops of Halberstadt.

OSCILLA, a word applied in Latin usage to small figures, most commonly masks or faces, which were hung up as offerings to various deities, either for propitiation or expiation, and in connexion with festivals and other ceremonies. It is usually taken as the plural of oscillum (dimin. of os), a little face. As the oscilla swung in the wind, oscillare came to mean to swing, hence

OSCILLOGRAPH. In connexion with the study of alternating or varying electric current, appliances are required for determining the mode in which the current varies. An instrument for exhibiting optically or graphically these variations is called an oscillograph, or sometimes an ondograph. Several methods have been employed for making observations of the form of alternating current curves-(1) the point-by-point method, ascribed generally to Jules Joubert; (2) the stroboscopic methods, of which the wave transmitter of H. L. Callendar, E. B. Rosa, and E. Hospitalier are examples; (3) methods employing a high-fre quency galvanometer or oscillograph, which originated with A. E. Blondel, and are exemplified by his oscillograph and that of W. Duddell; and (4) purely optical methods, such as those of I. Fröhlich and K. F. Braun.

In the point-by-point method the shaft of an alternator, or an alternating current motor driven in step with it, is furnished with an insulating disk having a metallic slip inserted in its edge. Against this disk press two springs which are connected together at each revolution by the contact of the slip at an assigned instant during the phase of the alternating current. This contact may be made to close the circuit of a suitable voltmeter, or to charge a condenser not be the average or effective voltage of the alternator, but the in connexion with it, and the reading of the voltmeter will therefore instantaneous value of the electromotive force corresponding to that instant during the phase, determined by the position of the rotating contact slip with reference to the poles of the alternator, If the contact springs can be moved round the disk so as to vary the instant of contact, we can plot out the value of the observed instantaneous voltage of the machine or circuit in a wavy curve, showing the wave form of the electromotive force of the alternator. This process is a tedious one, and necessarily only gives the average form of thousands of different alternations.

driven in step with the periodic current in the circuit being tested In the Hospitalier ondograph, a synchronous electric motor drives a cylinder of insulating material having a metallic slip let into its edge. This cylinder is driven at a slightly lower speed than that of synchronism. Three springs press against the cylinder and make contact for a short time during each revolution, so that a condenser is charged by the circuit at an assigned instant during the alternating current phase, and then subsequently connected to a voltmeter. This process, so to speak, samples or tests the varying electromotive phase and measures it on a voltmeter. Owing to the fact that the force of the alternating current at one particular instant during the cylinder is losing or gaining slightly in speed on the circuit periodicity. the voltmeter goes slowly, say in one minute, through all the phases

1 E. Hospitalier, "The Slow Registration of Rapid Phenomena by Stroboscopic Methods," Journ. Inst. Elec. Eng. (London, 1904), 33175. In this paper the author describes the "Ondographe" and Puissancegraphe." See also a description of the ondograph in the Electrical Review, (1902), 50, 969.

of voltage which are performed rapidly during each period by the
alternating current. The voltmeter needle may then be made to
record its variations graphically on a drum covered with paper and
so to delineate the wave form of the current. The process is analo-
gous to the optical experiment of looking at a quickly rotating wheel
or engine through slits in a disk, rotating slightly faster or slower
than the object observed. We then see the engine going through all
its motions but much more slowly, and can follow them easily. In
another form devised by Callendar, a revolving contact disk is
placed on the shaft of an alternator, or of a synchronous motor
driven by the alternating current under test. A pair of contact
springs are slowly shifted over so as to close the circuit at successive
assigned instants during a complete phase. The electromotive
force so selected is balanced against the steady potential difference
produced between a fixed and a sliding contact on a wire traversed
by another steady current, and if there is any difference between
this last, the potential difference, and the instantaneous potential
difference balanced against it, a relay is operated and sets in action
a motor which shifts the contact point along the potentiometer na obnu er
wire and so restores the balance. This contact point also carries a
pen which moves over a rotating drum covered with paper. As
the brushes are slowly shifted over on the revolving contact so as
to select different phases of the alternating electromotive force,
the pen follows and draws a curve delineating the wave form of that
electromotive force or current. An instrument devised by E. B.
Rosa is not very different in construction. A commutator method
has also been devised by T. R. Lyle (Phil. Mag., November
1903, 6. 517) in which at an assigned instant during the phase a
selection is made from the periodic current and measured on a
galvanometer. ad
mivil
or agront souhai o
The oscillographs of A. E. Blondel and W. Duddell operate on a
different principle. They consist essentially of a galvanometer of
which the needle or coil has such a short natural periodic time that
it can follow all the variations of a current which runs through its
cycle in say th second. This needle or coil must be so damped
that when the current is cut off it returns to zero at once without
overshooting the mark. By means of an attached mirror and
reflected ray of light the motion of the movable system can be indi-
cated on a screen. This ray is also given a periodic motion of the
same frequency by reflection from a separate oscillating mirror
so as to make the two motions at right angles to one another, and
thus we have depicted on the screen a bright line having the same
form as the periodic current being tested. In W. Duddell's oscillo-
graph (fig. 1) the galvanometer part consists of an electromagnet
in the field of which is stretched a loop of very fine wire. To this is
attached a mirror; hence, if a current goes up one side of a loop and
down another, the wires are oppositely displaced in the field. The
loop and mirror move in a cavity full of oil to render the system
dead-beat. A ray of light is reflected from this mirror and frometida lov
another mirror which is rocked by a small motor driven off the same
circuit, so that the ray has two vibratory motions imparted to it
at right angles, one a simple harmonic motion and the other a motion
imitating the variation of the current or electromotive force under
test. This ray can be received on a screen or photographic plate, bo
and thus the wave form of the current is recorded. In the Duddell
oscillograph it is usual to place a pair of loops in the magnetic field,
each with its own mirror, so that a pair of curves can be delineated
at the same time, and if there is any difference in phase between
them, it will be detected. Thus we can take two curves, one showing
the potential difference at the end of an inductive circuit, and the
other the current flowing through the circuit. In one form of
Blondel's oscillograph, the vibrating system is a small magnetic
needle carrying a mirror, but the principle on which it operates
is the same as that of the instrument above described. The oscillo
graph can be made to exhibit optically the form of the current curve
in non-cyclical phenomena, such as the discharge of a condenser.
In this case the large vibrating mirror must be oscillated by a
current from an alternator, on the shaft of which is a disk of non-
conducting material with brass slips let into it and so arranged with
contact brushes that in each period of the alternator a contact is
made, charging say a condenser and discharging it through the
oscillograph. In this way an optical representation is obtained of
the oscillatory discharge of the condenser. A form of thermal
Oscillograph has been devised by J. T. Irwin (Jour. Inst. Elec. Eng.
Lond. 1907, 39. 617). In this instrument the periodic current, the
time variation of which is being studied, passes through a pair of fine
wires or strips, going up one wire and down the other. These wires
are also traversed in the same direction by a constant current from
a battery. The two currents are therefore added in one wire and
subtracted in the other, and produce a differential heating effect
which causes unequal expansion, and this in turn is made to tilt a

1H. L. Callendar, An Alternating Cycle Curve Recorder," Electrician, 41. 582.

E. B. Rosa," An Electric Curve Tracer," Electrician, 40. 126. See Assoc. Franc pour l'Avanc, des Sciences (1898), for a paper on oscillographs describing Blondel's original invention of the Oscillograph in 1891. 9

Electrician (1897). 39. 636.b oels 998

diw,euibig 12 to 150rb
unam 1 13dest bas drobFIG. 1bow big sige diwa
causes a periodic displacement of
the 2
cathode ray and elongates th
the
patch of light into a bright line. If this patch is also given a dis-
placement in the direction of right angles by examining it in a
steadily vibrating mirror, we see a wavy or oscillatory line of light
which is an optical representation of the wave form of a current in
the coils embracing the Braun tube.)

References. See J. A. Fleming, A Handbook for the Electrical Laboratory and Testing Room, vol. i. (London, 1901), which contains a list of original papers on the oscillograph; Id., The Principles of Electric Wave Telegraphy (London, 1906), which gives illustrations of the use of the oscillograph and the Braun cathode ray tube in depicting condenser discharges; also, for the development of the oscillograph, A. E. Blondel, Oscillographs New Apparatus for registering Electrical Oscillations" (a short description of the bifilar and soft iron oscillographs), Comptes rendus (1893), 116, 502: Id., "On the Determination and Photographic Registration of Periodic Curves, La Lumière électrique (August 29th, 1901); Id.,

See K. F. Braun, Wied. Ann. (1897), 60,552; H. M. Varley. Phil. Mag. (1902), 3500; and J. M. Varley and W. H. F. Murdock, On some Applications of the Braun Cathode Ray Tube." Electr "Electrician (1905), 55. 335530: we of neem of sin rolli barwadi ai gauwe olliozo