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- CHRIS TIS ON underneath the fortress of Akershus. These works are on 14th November 1879, in the throne-room of the intended to be the first in a general rearrangement of the Imperial palace, the archduchess solemnly abdicated all entire harbour of the city. Population (1885), 128,301, her rights of succession in Austria, in accordance with the counting in the suburbs; (1891), 151,239; (1898), 203,337, law obliging all princesses of the Imperial house to do so of whom 93,695 males, 109,642 females; (1900), 225,686. when they wed a foreign prince. On 17th November the
numerous suite, Christiansand, a fortified seaport town of archduchess and her mother, with a Norway, on the S. coast.' It is an important
port of call for started for Spain, arriving at the royal castle of El Pardo, the Baltic steamboats, and a fishing centre.
near Madrid, on 24th November. The wedding took
It was burn down in 1892, and subsequently rebuilt of brick. It ex
place in the Atocha cathedral, on 29th November, in great ports timber (nearly 3 million cubic feet annually), wood- Christina bore her husband two daughters, before he died
state, and was followed by splendid festivities. Queen pulp, paper, fish, and felspar. The total trade is under
in 1885–Dona Mercedes, born 11th September 1880, and half a million sterling. Christiansand owns about 100 vessels of 52,000 tons. An impetus was given to the her husband's lifetime the young queen kept studiously
An impetus was given to the Dona Maria Theresa, born 12th November 1882. During trade and tourist traffic by the opening of the Sætersdal railway, tapping the interior, in 1895-96.
apart from politics, so much so that her inexperience
Sawmills, wood-pulp factories
, shipbuilding yards, and mechanical caused much anxiety in November 1885, when she was workshops are the principal industrial works. The
called upon to take the arduous duties of regent. cathedral was rebuilt after a fire in 1880. Population
the long minority of the posthumous son of Alfonso XII.,
the present King Alfonso XIII., the Austrian Queen-Regent (1875), 11,766 ; (1900), 14,007.
acted in a way that obliged even the adversaries of the Christianstad, a fortified town of Sweden, on a throne and the dynasty to respect the mother and the peninsula which juts out into Lake Sjövik, an expansion woman. The people of Spain, and the ever-restless civil of the river Helge, 10 miles from the Baltic and 66 miles E. and military politicians, found that the gloved hand of from Helsingborg by rail. It is the headquarters of several their constitutional ruler was that of a strong-minded and railway companies, and has flour mills, engineering works, tenacious regent, who often asserted herself in a way that distilleries, a weaving mill, sugar factory, &c., and exports surprised them much, but always, somehow, commanded granite and wood-pulp, and imports coal (40,000 to 70,000 obedience and respect. More could not be expected by a tons), and wheat and rye. In 1896-97 its harbour at foreign ruler from a nation little prone to waste attachAhus (pop. 1547) was enlarged and deepened to admit ment or demonstrative loyalty upon anybody not Castilian vessels drawing 18 ft., and a new entrance channel made. born and bred. In 1899 it was entered by 530 vessels of 100,150 tons. A new town hall was built in 1889. Population (1880), province of Vermland, Sweden, near the N.E. corner of Lake
Christinehamn, or KRISTINEHAMN, a town of the 9203; (1900), 10,318.
Wener, 25 miles by rail E. by S. from Carlstad. It has Christiansund, a seaport town of Norway, co. ironworks, a tobacco factory, &c., and large fairs are held Roinsdal, 83 miles W.S. W. from Trondhjem. It exports every April and October. A part of the town was burnt cod-fish, herrings, cod-liver oil, fish manure, &c., to the down in 1893. Population (1880), 5039; (1900), 6775. annual value of £350,000 to £550,000, and imports salt, coal, and colonial wares to about £55,000. Since 1894
Christison, Sir Robert, BART. (1797-1882), butter has been exported to Great Britain. In 1892 an Scottish toxicologist and physician, was born in Edinburgh outlook tower was erected to commemorate the 150th
on 18th July 1797. After graduating at the university anniversary of the founding of the town. Population
of that city in 1819, he spent a short time in London, (1875), 8251; (1898), 11,68
studying under Abernethy and Lawrence, and in Paris,
where he learnt analytical chemistry from Robiquet and Christina, Maria Christina Henrietta heard lectures by Orfila, the famous toxicologist. In Désirée Félicité Rénière, QUEEN-REGENT OF 1822 he returned to Edinburgh as professor of Medical SPAIN (1858- -), widow of Alfonso XII. and mother of Jurisprudence, and set to work to organize the study of Alfonso XIII., was born at Gross Seelowitz, in Austria, on his subject on a sound basis. On poisons in particular 21st July 1858, being the daughter of the Archduke Charles he speedily became a high authority; his well-known Ferdinand and the Archduchess Elizabeth of Austria. She book on them was published in 1829, and in the course was brought up by her mother as a rigid Catholic, and of his inquiries he did not hesitate to try such daring great care was taken with her education. At eighteen she experiments on himself as taking large doses of Calabar was appointed, by the Emperor Francis Joseph, abbess of bean. His attainments in medical jurisprudence and the House of Noble Ladies of Saint Theresa in Prague, toxicology procured him the appointment, in 1829, of where she made herself very popular and distinguished medical officer to the Crown in Scotland, and from that herself by her intellectual parts. It is said that at the time till 1866 he was called as a witness in many celebrated Court of Vienna the archduchess saw the young Prince criminal cases. In 1832 he gave up the chair of Medical Alfonso of Spain when he was only a pretender in exile, Jurisprudence and accepted that of Medicine and Therabefore the restoration of the Bourbons. A few years later, peutics, which he held till 1877; at the same time he when Alfonso XII. had lost his first wife and cousin, became professor of Clinical Medicine, and continued in Queen Mercedes, daughter of the duc de Montpensier, that capacity till 1855. His fame as a toxicologist and his ministers, especially Señor Canovas, urged him to medical jurist, together with his work on the pathology marry again. He told them that if he did so it would of the kidneys and of fevers, secured him a large private only be with the young Austrian Archduchess Maria practice, and he succeeded to a fair share of the honours Christina. After some negotiations between the two that commonly attend the successful physician, being Courts and Governments, it was agreed that the Arch- appointed physician to Queen Victoria in 1848 and reduchess Elizabeth and her daughter should meet Alfonso ceiving a baronetcy in 1871. Among the books which XII. at Arcachon, in the south of France, where a few he published were a treatise on Granular Degeneration of days' personal acquaintance was sufficient to make both the Kidneys (1839), and a Commentary on the Pharmacome to a decision. The duke of Bailen went officially to copoeias of Great Britain (1842). Sir Robert Christison, Vienna to get the emperor of Austria's authorization, and who retained remarkable physical vigour and activity CHRONOGRAPHS 63 down to extreme old age, died at Edinburgh on 23rd | although the rocks of the southern coast of Java in their general January 1882.
characters and succession resemble those of Christmas Island,
there lies between them an abysmal trough 18,000 feet in depth, Christmas Island, a British possession under which renders it scarcely possible that they were deposited in a
continuous area, for such an enormous depression of the sea-floor the government of the Straits Settlements, situated in the eastern part of the Indian Ocean (in 10° 25' S. lat., also Christmas Island. One of the main purposes of the explora
could hardly have occurred since Miocene times without involving 105° 42' E. long.), about 190 miles S. of Java. It is tion was to obtain light on the question of the foundation of not known when and by whom the island was discovered, atolls. As a result of the investigation it has been found that but under the name of "Moni it appears on a Dutch chart theory of atoll formation" does not exist, and although there
“the great thickness of reef limestone required by the Darwinian of 1666. It was first visited in 1688 by Dampier, who
may be some evidence that subsidence did occur in the earlier found it uninhabited. In 1886 Captain Maclear of H.M.S. history of the island, it is clear that it was neither continuous for Flying Fish, having discovered an anchorage in a bay any long period nor of any great extent” (Andrews). If Christwhich he named Flying Fish Cove, landed a party and
mas Island cannot, perhaps, be proved to have been a typical made a small but interesting collection of the flora and atoll, it can, however," be shown that at one time it must have
consisted of reefs and islands approximating very nearly to those fauna. In the following year Captain Aldrich on H.M.S. seen on atolls which are regarded as typical, and the determinaEgeria visited it, accompanied by Mr J. J. Lister, F.R.S., tion of the nature of the foundation upon which those reefs who formed a larger biological and mineralogical collection.
and islands rested is, at least, a step in the right direction ”
(Andrews). Among the rocks then obtained and submitted to Sir John
Flora and Fauna.—The flora consists of 129 species of angioMurray for examination there were detected specimens of sperms, 1 Cycas, 22 ferns, and a few mosses, lichens, and fungi, nearly pure phosphate of lime, a discovery which eventu- 17 of which are endemic, while a considerable number — not ally led, in June 1888, to the annexation of the island specifically distinct-form local varieties nearly all presenting to the British Crown. Soon afterwards a small settle Indo-Malayan a flinities, as do the single Cycas, the ferns, and the
cryptogams. As to its fauna, the island contains 319 species of ment was established in Flying Fish Cove by Mr G. animals—54 only being vertebrates—145 of which are endenic. Clunies Ross, the owner of the Keeling Islands, which A very remarkable distributional fact in
A regard to them, and one lie about 750 miles to the westward. In 1891 Mr Ross not yet fully explained, is that a large number show affinity with and Sir John Murray were granted a lease, but on the species in the Austro-Malayan rather than in the Indo-Malayan,
their nearer, region. The ocean currents, the trade-winds blowfurther discovery of phosphatic deposits they disposed of ing from the Australian mainland, and north-westerly storms from their rights in 1897 to the company now in possession. the Malayan islands, are no doubt responsible for the introducIn the same year a thorough scientific exploration was
tion of many, but not all, of these Malayan and Australasian made, at the cost of Sir John Murray, by Mr C. W. species.
Climate.—The climate is healthy, the temperature varying Andrews, of the British Museum.
from 75° to 84° F. The prevailing wind is the S. E. trade, which Physical Features and Geology.—The island is a quadrilateral | blows the greater part of the year. The rainfall in the wet with hollowed sides, about 12 miles in greatest length and 9 in
season is heavy, but not excessive, and during the dry season extreme breadth. It is about 190 miles from the nearest land, the ground is refreshed with occasional showers and heavy dews. and is probably the only tropical island that had never been Malarial fever is not prevalent, and it is interesting to note that inhabited by man. When the first settlers arrived, in 1897, it was there are no swamps or standing waters on the island. covered with a dense forest of great trees and luxuriant under- See ANDREWS, C. W. A Monograph of Christmas Island shrubbery. The settlement in Flying Fish Cove now numbers (Indian Ocean), London, 1900, to which the present writer some 250 inhabitants, consisting of Europeans, Sikhs, Malays, has been greatly indebted.
(H. O. F.) and Chinese, by whom roads are being cut and patches of cleared ground cultivated. The island is the flat summit of a submarine
Chronographs. In the article GUNNERY (Ency. mountain more than 15,000 feet high, the depth of the platform Brit. vol. xi.) descriptions were given of some chronographs from which it rises being about 14,000 feet, and its height above adapted for the determination of the velocities of projecthe sea being upwards of 1000 feet. The submarine slopes are
tiles. Some additional forms of instruments both for this steep, and within 20 miles of the shore the depth of the sea reaches 2400 fathoms. It consists of a central plateau descending
and for other purposes are here described. to the water in three terraces, each with its “tread” and “rise. Gun Chronographs.—Probably the earliest forms of chronographs, The shore terrace descends by a steep cliff to the sea, forming the not based on the ballistic pendulum method, are due to Colonel “rise” of a submarine "tread” in the form of fringing reef which Grobert, 1804, and Colonel Dabooz, 1818, both officers of the French surrounds the island and is never uncovered, even at low water, army. except in Flying Fish Cove, where the only landing-place exists. In the instrument by Grobert two large discs, attached to the The central plateau is a plain whose surface presents “rounded, same axle 13 ft. apart, were rapidly rotated ; the shot pierced flat-topped hills and low ridges and reefs of limestone,” with each disc, the angle between two holes giving the time narrow intervening valleys. On its northern aspect this plateau of flight of the ball, when the angular velocity of the discs was has a raised rim having all the appearances of being once the
known. In the instrument by Colonel Dabooz a cord passing margin of an atoll. On these rounded hills occurs the deposit of over two light pulleys, one close to the gun, the other at a given phosphate of lime which gives the island its commercial value. distance from it, was stretched by a weight at the gun end and by The phosphatic deposit has doubtless been produced by the long- a heavy screen at the other end. Behind this screen there was continued action of a thick bed of sea-fowl dung, which con
a fixed screen. The shot cut the cord and liberated the screen, verted the carbonate of the underlying limestone into phosphate. which was perforated during its fall. The height of fall was The flat summit is formed by a succession of limestones—all measured by superposing the hole in the moving screen upon that deposited in shallow water—from the Eocene (or Oligocene) up
in the fixed one. This gave the approximate time of flight of the to recent deposits in the above-mentioned atoll with islands on its shot over a given distance, and hence its velocity. reef. The geological sequence of events appears to have been In the early form of chronoscope invented by Wheatstone in the following After the deposition of the Eocene (or Oligocene) 1840 the period of time was measured by means of a species of limestone-which reposes upon a floor of basalts and trachytes— clock, driven by a weight; the dial pointer was started and basalts and basic tuffs were ejected, over which, during a period stopped by the action of an electromagnet which moved a pawl of very slow depression, orbitoidal limestones of Miocene age- engaging with a toothed wheel fixed on the axle to which the dial which seem to make up the great mass of the island—were pointer was attached. The instrument applied to the determinadeposited ; then elapsed a long period of rest, during which the tion of the velocity of shot is described thus by Wheatstone atoll condition existed and the guano deposit was formed ; from “A wooden ring embraced the mouth of the gun, and a wire then down to the present time there has succeeded a series connected the opposite sides of the ring. At a proper distance the of sea-level subsidences, resulting in the formation of the target was erected, and so arranged that the least motion given to terraces and the accumulation of the detritus now seen on the it would establish a permanent contact between two metal points. first inland cliff, the old submarine slope of the island. The One of the extremities of the wire of the electromagnet (before occurrence of such a series of Tertiary deposits appears to be un- mentioned) was attached to one pole of a small battery ; to the known elsewhere. The whole series was evidently deposited in other extremity of the electromagnet were attached two wires, one shallow water on the summit of a submarine volcano standing in of which communicated with the contact piece of the target, and its present isolation, and round which the ocean floor has prob- the other with one of the ends of the wire stretched across the ably altered but a few hundred feet since the Eocene age. Thus | mouth of the gun ; from the other extremity of the voltaic battery
two wires were taken, one of which came to the contact piece of drum, divided on its edge so that when a vernier is used a minute . the target, and the other to the opposite extremity of the wire of angle may be read, is rotated rapidly by a motor at a practically across the mouth of the gun. Before the firing of the gun a con- uniform speed. The points of a row of steel-pointed pips, screwed tinuous circuit existed, including the gun wire; when the target into a frame of ebonite, can be brought within to inch of the was struck the second circuit was completed; but during the surface of the drum. Each pin is a part of the secondary circuit passage of the projectile both circuits were interrupted, and the of an induction coil, the space between the pins and the drum duration of this interruption was indicated by the chronoscope.” forming spark gaps. The drum is rubbed over with a weak solution
Professor Henry (Journal Franklin Inst., 1886) employed a of paraffin wax in benzol, which causes the markings produced by cylinder driven by clockwork, making ten revolutions per second. the sparks to be well defined. The records are read by means of The surface was divided into 100 equal parts, each equal to Toto a fine hair stretched along the drum and just clear of it, the dots second. The time marks were made by two galvanometer needles, being located under the hair by means of a lens. The velocity of when successive screens were broken by a shot. Henry also used rotation is found by obtaining spark marks, due to the primary an induction-coil spark to mark the cylinder, the primary of the circuits of two induction coils being successively broken by a coil being in circuit with a battery and screen. This form of weight falling and knocking over two light levers. The distance chronograph is in many respects similar to the instrument of between the levers is about 3.77 inch, and the time of fall between Konstantinoff, which was constructed by Breguet and has been the levers is 0.018948 sec. In practice two drop weights are used, sometimes attributed to him (Les Comptes Rendus, 1845). This to avoid the chance of an experiment being wasted. This chronochronograph consisted of a cylinder 1 m. in circumference and graph has been used for finding the velocity of projectiles after 0:36 m. long, driven by clockwork, the rotation being regulated by leaving the gun, and also for finding the rate at which a shot a governor provided with wings. A small carriage geared to the traverses the bore. For the latter purpose the shot successively wheelwork traversed its length, carrying electromagnetic signals. cuts insulated wires fized in plugs screwed into the gun at known The electric chronograph signal usually consists of a small arma- intervals; each wire forms a part of the primary of an induction ture (furnished with a style which marks a moving surface) moving coil, and as each is cut a dot is made on the rotating drum by the in front of an electromagnet, the armature being suddenly pulled induced spark. off the poles of the electromagnet by a spring when the circuit is Jervis-Smith’s tram chronograph was devised for measuring periods broken (Journal of Physiology, vol. ix. p. 408). The signals in of time varying from about one-fourth to one twenty-thousandth Breguet's instrument were in a circuit, including the screens and part of a second (Proc. Roy. Soc. vol. xlv. p. 452.
452. Improved batteries of a gun range. The measurement of time depended on from Pat. 1894. The Tram Chronograph, by F. J. Jervis-Smith, the regularity of rotation of the cylinder, on which each mm. F.R.S.). It consists of a metal girder having a T-shaped end. This represented roto second.
carries two parallel steel rails, the edges of which lie in the same In the Navez chronograph (1848) the time period is found by vertical plane. The girder is supported at its end, and at the means of a pendulum held at a large angle from the vertical by an extremities of the T-piece, on the V-groove, trihedral hole, and electromagnet, which is in circuit with a screen on the gun range. plane system. A carriage or tram furnished with three grooved When the shot cuts this screen, the circuit is broken and the wheels runs on the rails, and a slightly-smoked glass plate is pendulum liberated and set swinging. When the next screen on attached to its vertical side. The tram in the original instrument the range is broken by the shot, the position of the pendulum is was propelled by a falling weight, but in an improved form one recorded and the distance it has passed through measured on a or more spiral springs are employed. All time traces are made divided arc.
From this the time of traversing the space between immediately after the propelling force has ceased to act. The the screens is deduced. By means of an instrument known as a tram is brought to rest by a gradually applied brake, consisting disjunctor (Ency. Brit. vol. xi. p. 300) the instrumental time-loss of two crossed leather bands stretched by two springs ; a projecor latency of the chronograph is determined. In Benton's chrono. tion from the tram runs between the bands, and brings it to rest graph (1859) two pendulums are liberated, in the same manner as with but little lateral pressure. When, for certain physiological in the instrument of Navez, one on the cutting of the first screen, experiments, a low velocity of traverse is required, a heavy flythe other on the cutting of the second. The difference between wheel is mounted on the tram and geared to its wheels. A pillar the swings of the two pendulums gives the time period sought for. also mounted on the hole, groove and plane method, is placed The disjunctor is also used in connexion with this instrument. vertically in front of the glass, to carry the electromagnetic signals, In Vignotti's chronograph (1857) again a pendulum is employed, which can be brought into contact with the glass by means of a furnished with a metal point, which moves close to paper impreg- tangent-screw. A standard fork by Koenig fixed to a pillar also nated with ferro-cyanide of potassium. The gun-range screens makes a trace on the glass, being automatically thrown into are included in the primary circuits of induction coils ; when these vibration. Tuning - forks may be calibrated by obtaining two circuits are broken a spark from the pointer marks the paper. signal markings on the plate, controlled by a standard clock of From these marks the time of traverse of the shot between the known rate. Two motions of a slide on the pillar, viz., of rotation screens is determined.
and translation, allow a number of observations to be made. The Colonel Sebert (Extraits du Mémorial de l'Artillerie de la Marine) traces are counted out on a sloping glass desk, and the time of devised a chronograph to indicate graphically the motion of recoil flight of a projectile between two or more screens is found. When of a cannon when fired. A pillar fixed to the ground at the side very close readings are required, they are made by means of a of the gun-carriage supported a tuning-fork, the vibration of traversing micrometer microscope. If the instrument is used for which was maintained electrically. The fork was provided with gun work, the tram is driven at full speed ; when the distance a tracing point attached to one of the prongs, and so adjusted that between the screens is known, and also the time of flight, the it drew its path on a polished sheet of smoke - blackened metal midpoint velocity is found by applying Bashforth's formula. attached to the gun-carriage, which traversed past the tracing When the velocity of shot from a shot-gun has to be found, a thin point, when the gun ran back. The fork used made 500 com- wire stretched across the muzzle takes the place of the first screen, plete vibrations per second. A central line was drawn through and a thin sheet of metal or cardboard carrying an electric conthe curved path of the tracing point, and every entire vibration tact, or a Branly coherer, takes the place of the second screen. cut the straight line twice, the interval between each intersection The electric firing circuit is provided with a safety key attached equalling Tobo second. The diagram so produced gave the total by a cord to the man who loads the gun and prepares the electric time of the accelerated motion of recoil of the gun, the maximum fuse, thus preventing him from getting into the line of fire when velocity of recoil, and the rate of acceleration of recoil from the the gun is fired by the chronograph. (Pat. Record, 1897.) The beginning to the end of the motion. By means of an instrument tram, when the instrument is adjusted, has a practically constant furnished with a microscope and micrometers, the length and velocity of traverse. amplitude, and the angle at which the curved line cut the central The polarizing photo-chronograph, designed and used by Dr A. line, were measured. At each intersection (according to the in- Cushing Crehore and Dr G. Owen Squier at the United States ventor) the velocity could be deduced. The motion at any inter- Artillery School (Journal United States Artillery, 1895, vol. vi. section being compounded of the greatest velocity of the fork, p. 271), depends for its indications upon the rotation of a beam of while passing through the midpoint of the vibration and the light by a magnetic field, produced by a solenoidal current, which velocity of recoil
, the tangent made by the curve with the straight is opened and closed by the passage of the projectile. The general line represents the ratio of the velocity of the fork to the velocity arrangement is as follows :- A beam of light from an electric lamp of recoil. If a be the amplitude of vibration, considered constant, traverses a lens, then a Nicol prism, next a glass cylinder furnished v the velocity of the fork at the midpoint of its path, r the with plane glass ends and coiled with insulated wire, then an velocity of recoil, a the angle made by the tangent to the curve analyser and two lenses, finally impinging on a photographic plate with the straight line at the point of intersection, and t the line to which rotation is given by an electric motor, the plane of of a complete vibration; then,
rotation being perpendicular to the direction of the beam of light. 2πα.
The same plate also records the shadow of a pierced projection
attached to a tuning-fork, light from the electric lamp being t
diverted by a mirror for this purpose. The solenoid used to proIn Colonel Watkin's chronograph ("Chronographs and their duce a magnetic field across the glass cylinder, which is filled with Application to Gun Ballistics,” Proc. Roy. Inst., 1896) a metal carbon bisulphide, is in circuit with a dynamo, resistances, and
the screens on the gun range. It is a well-known phenomenon in that second is divided into ten equal parts. The base of the physics that when, with the above-mentioned combination of triangle is always kept parallel with the line of dots. The papers, polarizing Nicol prism and analyser, the light is shut off by after they have been examined and the results registered, are kept rotating the analyser, it is instantly restored when the carbon for reference. bisulphide is placed in a magnetic field. This phenomenon is The observatory of Washburn, University of Wisconsin, is utilized in this instrument. The projectile, by cutting the wire furnished with a chronograph of the same type as that of Dent screens, causes the magnetic field to cease and light to pass. By (Annals Harvard Coll. Obs. vol. i. pt. ii. p. 31), but in this means of an automatic switch the projectile, after cutting a instrument the rotation of the cylinder is controlled by a double screen, restores the electric circuit, so that successive records are conical pendulum governor of peculiar construction. When the registered. After a record has been made it is read by means of a balls fly out beyond a certain point, one of them engages with a micrometer microscope, the angle moved through by the photo- hook attached to a brass cylinder which embraces the vertical axle graphic disc is found, and hence the time period between two loosely. When this mass is pulled aside the work done on it events. In the photo-chronograph described in Untersuchungen diminishes the speed of the governor. The pendulum ball usually über die Vibration des Gewehrlaufs, by C. Cranz and K. R. Koch, strikes the hook from 60 to 70 times per minute. Governors on München, 1899, also note on the same, Nature, vol. lxi. p. 58, this principle were adopted by Alvan Clark for driving heliostats a sensitive plate moving in a straight line receives the record of in the United States Transit of Venus Expedition, 1874. the movement of the barrels of firearms when discharged. It was Acoustic Chronographs.--A chronograph was devised by Regnault mainly used to determine the “angle of error of departure" in (Acad. des Sc., 1868) to determine the velocity of sound propaballistics.
gated through a great length of pipe. A band of paper 27 mm. Astronomical Chronographs.—The astronomical chronograph is wide was continuously unrolled from a bobbin by means of an an instrument whereby an observer is enabled to register the time electromagnetic engine. In its passage over a pulley it passed of transit of a star on a sheet of paper attached to a revolving over a smoky lamp flame, which covered it with a thin deposit of cylinder. A metal cylinder covered with a sheet of paper is carbon. It next passed over a cylinder in contact with the style rotated by clockwork controlled by a conical pendulum, or by a of a tuning-fork kept in vibration by electromagnets placed on centrifugal clock governor such as is used for driving a telescope. either side of its prongs, the current being interrupted by the By means of a screw longer than the cylinder, mounted parallel fork; it was also in contact with an electric signal controlled by with the asis of the cylinder and rotated by the clockwork, a a standard clock. Also an electromagnetic signal marked the carriage is made to traverse close to the paper. In some instru- beginning and end of a time period. Thus three markings were ments this carriage is furnished with a metal point, and in others registered on the band, viz., the time of the pendulum, the with a stylographic ink pen. The point or pen is made to touch vibrations of the fork, and the marking of the signal due to the the paper by an electromagnet the electric current of which is opening and closing of the current by electrical contacts attached closed by the observer at the transit instrument, and a mark is to diaphragms on which the sound wave acted. The contacts recorded on the revolving cylinder. The movement of the same consisted of minute hammers resting on metal points fixed to the point or pen is also controlled by a standard clock, so that at the centre of diaphragms which closed the end of the experimental end of each second a mark is made. The cylinder makes one pipes. The signal marked the instant at which a sound wave revolution per minute, and the minute is indicated by the omission impinged on a diaphragm. The markings on the paper band gave of the mark. In Dent's form (Nature, vol. xxiii. p. 59) continuous the period of time between two events, and the number of vibraobservations can be recorded for 63 hours. The conical pendulum tions of the tuning-fork per second were estimated by means of used to govern the rotation of the cylinder was the invention of markings due to the clock. The sound wave was usually originSir G. B. Airy. The lower end is geared to a metal plate ated by firing a pistol into the pipe furnished with diaphragms and which sweeps through an annular trough filled with glycerine and contact pieces. water. When the path of the pendulum exceeds a certain In the chronographic use of the Morse telegraph instrument diameter it causes the plate to enter the liquid more deeply, its (Stewart and Gee, Elementary Practical Phys. p. 234) a circuit motion being thereby checked ; also, when the pendulum moves in is arranged which includes a seconds pendulum furnished with a a smaller circle, the plate is listed out of the liquid and the fine platinum wire below the bob, which sweeps through a small resistance is diminished in the same proportion as the force. The mass of mercury forming a part of the circuit. There is a Morse compensatory action is considerable ; doubling the driving power key for closing the circuit. A fast-running Morse instrument and produces no perceptible difference in the time. To prevent the a battery are placed across this circuit as a shunt. A succession injury of the conical pendulum and the wheel work by any sudden of dots is made on the paper ribbon by the circuit being closed by check of the cylinder, a ratch-wheel connexion is placed between the pendulum, and the space between each adjacent dot indicates the cylinder and the train of wheel work ; this enables the a period of one second's duration. Also, when the key is depressed, pendulum to run on until it gradually comes to rest.
a mark is made on the paper. To measure a period of time, the dulum, which weighs' about 18 lb, is compensated, and makes key is depressed at the beginning and end of the period, causing one revolution in two seconds ; it is suspended from a bracket by two dots to be made on the ribbon; the interval between these, means of two flexible steel springs placed at right angles to one when measured by the intervals due to the pendulum, gives the another.
length of the period in seconds, and also in fractions of a second, In the astronomical chronograph designed by Sir Howard Grubb, when the seconds' interval is subdivided into convenient equal F.R.S. (Proc. Inst. Mech. Eng., July 1888), the recording cylinders parts. This apparatus has been used in determination of the -two in number—are driven by a weight acting on a train of velocity of sound. In the break circuit arrangement of pendulum wheel work controlled by an astronomical telescope governor. key and Morse instrument the markings appear as breaks in a line The peculiar feature of this instrument is that the axle is geared to which would otherwise be continuous. This combination was ema shaft which communicates motion to the cylinders through a ployed by Professors Ayrton and Perry in their determination of mechanism whereby the speed of rotation is constantly corrected the acceleration of gravity at Tokio, 1877-78 (Proc. Phys. Soc. by a standard clock. Should the rotation fall below the correct London, vol. iii. p. 268), speed, it is automatically accelerated, and if its speed of rotation In the tuning-fork electro-chronograph attributed to Hipp a rises above the correct one, it is retarded. The accelerator and metal cylinder covered with smoked glazed paper is rotated retarder are thrown into action by electromagnets, controlled by a uniformly by clockwork, a tuning-fork armed with a metallic “detector” mounted on the same shaft. The rather complicated .
style being so adjusted that it makes a clear fine line on the mechanism employed to effect the correction is described and fully smoked paper. The tuning-fork is placed in the secondary illustrated in the reference given. The cylinders are covered with circuit of an induction coil, so that when the primary circuit is paper, but all the markings are made with a stylographic pen. The broken an induced spark removes a speck of black from the paper marks indicating seconds are dots, but those made by the observer and leaves a mark. The time period is deduced by counting the are short lines. When an observation is about to be made, the number of vibrations and fractions of vibration of the tuning-fork observer first notes the hour and minute, and, by pressing a contact as recorded by a sinuous line on the cylinder. In later forms of key attached to a flexible cord at the transit instrument, marks this instrument the cylinder advances as it rotates, and a spiral the paper with a letter in Morse telegraph characters, indicating line is traced. To obtain good results the spark must be very the hour and minute ; he then waits till a micrometer wire cuts a small, for when large it often leaps laterally from the end of the star and at the instant closes the circuit, so that the second and style, and does not give the true position of the style when the fraction of a second are registered on the chronograph paper. When circuit is broken. The same arrangement of tuning-fork and a set of observations have been taken, the paper is removed from revolving cylinder, with the addition of a standard clock, has the cylinder, and the time results are obtained by applying a been used by Mayer (Trans. National Academy of Sciences U.S. A. suitably divided rule to the marked paper, fractions of a second vol. iii.) and others for calibrating tuning-forks, and comparing being estimated by applying a piece of glass ruled with eleven their vibrations directly with the beats of the pendulum of a straight lines converging to a point. The ends of these lines on standard clock the rate of which is known. The pendulum the base of the triangle so formed are equidistant on one edge of makes and breaks the primary circuit by carrying a small platinum the glass, so that when the first and last lines are so placed as to wire through a small mercury meniscus. Better and apparently coincide with the beginning and end of the markings of a second, certain contacts can be obtained from platinum contact-pieces,
S. III. – 9
TA B L
pp. 42, 45.
brought together above the pendulum by means of a toothed Abth. 11, München, 1862, S. 361.-Fall-Myographion aufgestellt wheel on the scape-wheel arbor. Sparking at the contact points in der Wiener Weltausstellung in der Abtheilung für das Unteris greatly reduced by placing a couple of lead plates in dilute richtswesen von Ungarn, Budapest, 1873.—HENSEN. “Myograsulphuric acid as a shunt across the battery circuit.
phion mit vibratorischer Bewegung,” Arbeiten aus dem Kieler For physiological purposes.-Fick’s pendulum myograph ormuscle- physiol. Instit. 1868, S. 108. — BRÜCKE. Sitzungsber. d. Wiener trace recorder is described in Vierteljahrschr. der Naturforsch. Ges. Acad. LXXV. 3. Abth., Sep. Abdr, 1877.—PFLUEGER. "Myograin Zürich, 1862, s. 307, and in Text-book of Physiology, M. Foster, phion ohne Bewegung,” Untersuchungen über die Physiologie des
It was used to obtain a record of the contraction of Electrotonas. S. 106, Berlin, 1859. — POUILLET. Compt. Rend. a muscle when stimulated. In many respects the instrument is xix. p. 1384. 1844.—LUDWIG. “Kynographion.”—PFLUEGER. similar to the electro- ballistic chronograph of Navez. A long “Cylinder governed by conical pendulum,” Phys. der Menschen, pendulum, consisting of a braced metal frame, carries at its lower Munk.-YOUNG, Thos. 'Early form of cylinder chronograph, end a sheet of smoked glass. The pendulum swings about an Life in Motion, M‘Kendrick, p. 55. (ii.) Chronographs used in axis supported by a wall bracket. Previous to an experiment, gun work and for other purposes :—SABINE. Phil. Mag. 1876. the pendulum is held on one side of its lowest position by a spring -Schultz. Moisson, ed. Tanera. Paris. - PAUL LA Cour. La catch ; when this is depressed it is free to swing. At the end of Roue Phonique. Copenhagen, 1878. — MACH. Collected papers its swing it engages with another spring catch. In front of the on chronographs, Nature, vol. xlvii. p. 250.—Boys. Bullets moving glass plate a tuning-fork is fixed, also a lever actuated by photographed in flight,” B. A. meeting, Edinburgh, 1892 ; rethe muscle to be electrically stimulated. When the pendulum ported in Nature, vol. xlvii. p. 415. — PNEUMATIC TUBE Co., swings through its arc, it knocks over the contact key in the Paris. Chronograph,” Nature, vol. viii. p. 106. — FOSTER. primary circuit of an induction coil, the secondary of which is in Nature, vol. xiii. p. 139.-HOLDEN. Nature, vol. xxvi. p. 368. — connexion with the muscle. The smoked plate receives the traces D'ARSONVAL. La Lumière Electrique. 1887.-DUNN. “The of the style of the tuning-fork and of the lever attached to the Photo-Retardograph,” Journal U.S. Artillery, vol. vii. p. 29. muscle, and also the trace of an electromagnetic signal which DEPREZ. " Accélérographe,” La Méthode graphique, Marey, p. 174. marks the instant at which the primary circuit is broken. After Paris, 1878.-SIEMENS (Werner). “Electric spark chronograph,” the traces are made, they are ruled through with radial lines, Annalen der Phys., Poggendorff, 66. 1845. (F. J. J.-S.) cutting the three traces, and the time intervals between different parts of the muscle curve are measured in terms of the period of
Chronological Table.—The following table vibration of the tuning-fork, as in other chronographs in which the tuning-fork is employed.
of the leading events in every country in the world has In the spring myograph of Du Bois Reymond (Munk's Physiologie been prepared in continuation of the table published in der Menschen, p. 398) a smoked glass plate attached to a metal rod the ninth edition of this work, which brought down the is shot by a spiral spring along two guides with a velocity which
record to the close of 1875. It must always be diffiis not uniform. The traces of a style moved by the muscle under examination, and of a tuning-fork, are recorded on the glass plate,
cult to determine what events should or should not appear the shooter during its traverse knocking over one or more electric in such a chronicle, but in this brief abstract the aim has keys, which break the primary circuit of an induction co the been to include rather than to exclude, with a view to induced current stimulating the muscle.
making the table a really useful aide-mémoire :In the photo-electric chronograph devised by Mr G. J. Burch (Journal of Physiology, vol. xviii. p. 125; Electrician, vol. xxxvii. 1876. Chapter of Knights of the Star of India held by the p. 436) the rapid movements of the column of mercury in a Prince of Wales in Calcutta, January 1. Death of Francis Deák, capillary electrometer used in physiological research are recorded January 28. Administrative reform Note presented to Turkey by on a sensitive plate moving at a uniform angular velocity. The the Great Powers, January 31. Perak River insurgents defeated trace of the vibrating prongs of a tuning-fork of known period is by the British, February 4. Prince Bismarck's reply to the charge also recorded on the plate, the light used being that of the electric of warlike designs, February 10. Purchase of Suez Canal shares
The images of the meniscus of the mercury column and of voted by the House of Commons, February 21. Don Carlos retires the moving fork are focussed on the plate by a lens. Excellent from Spain, February 27. Incorporation of Khokand in the results have been obtained with this instrument.
Russian Empire, March 13. Royal Titles Bill passed by the House An important development of a branch of chronography is due of Commons, March 23. Philadelphia Centennial Exhibition to Marey (Comptes Rendus, 7 Août 1882, and Le Mouvement, par opened, May 10. British fleet arrives in Besika Bay, May 26. E. S. Marey, Paris, 1894), who employed a photographic plate for Turkish massacres in Bulgaria, May. Deposition of Sultan receiving successive pictures of moving objects, at definite times, Abdul Aziz, May 30. First railway opened in China, June 3. when investigating the movements of animals, birds, fishes, Death of Lord Sandhurst, June 23. (born, 1819). Slaughter of insects, and also microscopic objects such as vorticellæ. The United States troops by Sioux Indians, June 25. Death of Miss instrument in one of its forms consisted of a camera and lens. Harriet Martineau, June 27 (born, 1802). Servia and Montenegro In front of the sensitive plate and close to it a disc, pierced with declare war against Turkey, July 2. Mr Disraeli created Earl of radial slits, revolved at a given angular velocity, and each time a Beaconsfield, August 16. Deposition of Sultan Murad V., August slit passed by the plate was exposed. But since, in the time of 31. Sir T. Wade's treaty with Chipa ratified, September 17. passage of the space between the slits, the object had moved by a General Tchernaieff proclaims Prince Milan King of Servia, certain amount across the field of view, a fresh impression was September 20. Mr Goschen's financial mission to Egypt, October produced at each exposure. The object, well illuminated by sun- 14. Spanish army under General Martinez Campos sent to Cuba light, moved in front of a black background. Since the angular to suppress the insurrection, October 15. Capture of Alexinatz by velocity of the disc was known, and the number of slits, the time the Turks : Russian demand for an armistice between Turkey and between the successive positions of the object was also known. Servia, October 31. Speech by Lord Beaconsfield on the Turkish
Marey (La Méthode graphique, pp. 133, 142, 456), by means of question, November 9. Porfirio Diaz, having defeated the Govern-
18. Defeat of Japanese rebels near Kagosina, February 23. Death REFERENCES TO CHRONOGRAPHIC METHODS—(i.) Chronographs of Sir Jung Bahadur of Nepal, February 25. Peace treaty between used in Physiology:—HELMHOLTZ. Verhandlungen derphysikalisch- Turkey and Servia, March 1. Papal allocution on restriction of medicinischen Gesellschaft in Würtzburg. N. F. 1872, Bd. II. S. liberty, March 12. Protocol signed by the Great Powers regarding 147.-HARLESS. "Das Atwood'sche Myographion,” Abhandlungen the Eastern question, March 31. Arrival of Sir Bartle Frere at der k. Bayerischen Akademie der Wissenschaften. II. Cl. Bd. ix. Cape Town as High Commissioner, March 31. Annexation of