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contribute no less than from 16,000,000l. to 17,000,000l. per annum to the imperial revenue.

SPIROMETER, an ingenious instrument devised by Dr. Hutchinson for measuring the capacity of the chest, that is to say, the greatest quantity of air which can be taken into the lungs by a full inspiration. The instrument, which consists of a delicately balanced gasometer, with every adjustment necessary to insure great accuracy of measurement, is figured, and described, with the addition of needful tables of reference, at p. 152 of Hooper's Physician's Vade Mecum,' where also will be found a reference to the earlier attempts by Dr. Lyons and Mr. Abernethy to gauge the capacity of the lungs. Dr. Hutchinson's instrument has been largely used in insurance offices, but is gradually falling into disuse, in consequence chiefly of the time and care required to obtain satisfactory results.

SPLAYS, the sloping or receding sides of the doorways and windows in Gothic architecture. Splayed surfaces are a distinctive and effective characteristic of Gothic architecture; they seldom, if ever, occur in Greek or Roman buildings. [GOTHIC ARCHITECTURE, E. C. vol. iv. cols. 440 and 449.]

SPOIL, the property taken from a conquered enemy on the battle-field, consisting of the arms, accoutrements, and other personal effects, and even persons of the enemy. Amongst the ancient Egyptians, besides these, the heads and members of the dead were brought in and counted, and the living prisoners reduced to slavery formed part of the spoil. A considerable portion of the spoil was dedicated to the gods, and distributed amongst the temples of the country, while the leading officers received captives and other objects taken on the battle-field. The Assyrians in the same manner spoiled their enemies, and brought the heads of their foes and laid them in heaps before their victorious generals. Cattle and other animals were also often spoil of the victors. The Hebrews took spoil in the same manner as the Egyptians, the heads and members of the dead being brought into the camp and counted. A portion was taken to the treasury, and the more remarkable arms were suspended in the sanctuary. Amongst all these nations, the heads of enemies killed on the battle-field were carried home and affixed to gates or other places. The spoil was divided into two portions, and one or a half of the whole given to the army. Among the Greeks the spoil consisted chiefly of the garments and arms stripped from the dead or even living, standards, and other objects. These spoils were called skula or laphura. They were carried to the general or commander, who selected whatever he chose; other portions were given to those who distinguished themselves in the action, and the rest equally divided amongst the army. As with the oriental nations, a portion of it, often a tenth, was dedicated to the gods. Arms and other equipments were often made into a trophy, and erected on the battle-field to commemorate the defeat of the enemy, and to remain as an offering to the gods. Amongst the Romans the booty or spoil called spolia consisted of arms, weapons, and other things taken from the enemy on land, in addition to which the beaks or prows, rostra, of ships taken at sea were regarded as spoil. These were displayed, and adorned the vestibule of the houses of victorious generals and those who had been honoured with a triumph; or were placed in the temples. The spoils taken from the person of the general or leader of the enemy were the spolia opima. These were generally dedicated to the Jupiter of the Capitol. In modern times, the term spoil is confounded with booty, the Latin præda, and having been sold or converted into money, is divided according to certain rules amongst the army as prize-money.

SPOIL FIVE, a game at cards fashionable in England in the time of the Stuarts, under the name of " maw." It was subsequently called "five cards" (Compleat Gamester,' 1674), and was much played in Ireland, where it is still a favourite, and is known as spoil five.

Spoil five is played with a pack of fifty-two cards. Any number may play, from two to ten; but about five make the best game.

The deal is determined by distributing the cards face upwards one at a time to each player; the player who first has a knave dealt him is the dealer. The deal then proceeds in rotation to the left. The pack is cut to the dealer by the player on his right. The dealer re-unites the packets and gives five cards to each player in rotation, commencing with the one to his left. The cards are dealt by two or three at a time. If two are first given, two must first be dealt all round, and then three all round, and vice versa.

The card on the top of the pack after the hands are dealt is

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turned up for trumps, and is placed face upwards on the pack. When only two play, the game is sometimes varied by fiving it i. e., if the non-dealer is not satisfied with his cards, he asks the dealer to five it. If the dealer agrees, the trump card is removed, and the next card is turned up for trumps.

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During the deal each player pays to the pool a certain stake or number of counters, as agreed on. When the game is over the winner takes the pool; but if a spoil occurs (as will be explained), the pool remains, and each player puts an additional sum (generally half the original stake) into the pool, and so on after every spoil until a game is won.

If the turn-up card is an ace, the dealer has the privilege of robbing, i. e., of discarding any card from his hand (placing it face downwards under the pack), and of taking in the ace. The dealer must discard before the eldest hand plays, but the rob should not be completed by taking in the ace until it is the dealer's turn to play.

If any player holds the ace of the trump suit in his hand, he must rob. He is not bound to declare that he is about to rob until it is his turn to play, but he must declare before he plays by placing the rejected card face downwards on the table. If he neglects to do this, he loses the right of robbing, and forfeits the hand-i. e., he cannot win the game that hand, but he may play his cards and try to spoil it.

Some players make robbing optional; but this leads to concealment of the ace, and is not recommended.

Whether there is a rob or not, the hands are thus played: Each player plays one card in rotation, commencing with the one to the dealer's left, the dealer playing last. The cards played one by each player constitute a trick. The player of the highest spoil-five card (see order of the cards below) wins the trick. Trumps win other suits. The winner of the trick leads to the next, and so on, until the hand is played out, or until three tricks are won by one player.

When a trump is led the players must follow suit, except with special cards, presently to be mentioned. When a plain suit is led, any one may trump the trick, though able to follow suit; but a player holding no trump must follow suit, if able. This is usually expressed, "follow suit or play a trump ;" but this is not quite correct, as a player holding none of the suit led has the option of trumping or not. Provided the foregoing rules are complied with, a player is not bound to head the trick.

A player who wins three tricks in one hand wins the game. If no one wins three tricks, the game is spoilt. No spoil can take place with only two players.

The order of the cards at spoil five is peculiar, and some attention is required at first to master it. The order differs in red and black suits, and again in the trump suit.

In red suits not trumps the order of the cards is king (highest), queen, knave, ten, nine, eight, seven, six, five, four, three, two, ace (lowest).

In black suits not trumps the order is king (highest), queen, knave, ace, two, three, four, five, six, seven, eight, nine, ten (lowest).

The order of the cards below the knave is thus commonly expressed, "the highest in red, the lowest in black."

The ace of hearts always ranks as a trump. Therefore, in the above-mentioned order for red suits not trumps, the ace must be omitted from the heart suit.

In red suits when trumps the order of the cards is as follows:five (highest), knave, ace of hearts, ace of diamonds (when diamonds are trumps), king, queen, ten, nine, eight, seven, six, four, three, two (lowest).

In black suits when trumps the order is-five (highest), knave, ace of hearts, black ace, king, queen, two, three, four, six, seven, eight, nine, ten (lowest).

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The five of trumps, knave of trumps, and ace of hearts may renege-i. e., the player holding them is not bound to follow suit when an inferior trump is led. The five may renege to any trump; no trump can renege when the five is led. knave may renege to any trump except the five. If the knave is led, no trump can renege except the five. Similarly the ace of hearts may renege to any trumps except the five and the knave; if the ace of hearts is led, the five and knave of trumps can renege. Hearts need not be played to the ace of hearts led by players holding no trumps; the ace of hearts is a trump, and the rule about following suit only applies to the ace of hearts in its capacity as a trump.

It will be observed that the obligation to play a trump to these cards only applies to a lead of one of them, and is of no effect when they are played to a trick and not led,

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Spoil five is played in different ways. Sometimes spoils are dispensed with altogether, and the game is made a fixed number (twenty-five or forty-five), each trick made counting five to the winner of it. At forty-five, but not at twenty-five, the trick won by the best trump out counts ten, instead of five. If sufficient tricks are won to make game before the holder of the best trump plays it, the tricks have precedence. Robbing is always compulsory. If a player wins all five tricks he wins the game. This is called jinking it. Properly the jink belongs only to these games, but sometimes by agreement jinking is allowed at spoil five, the winner being paid in addition to the pool the amount originally staked by each player.

When jinking is allowed at spoil five, if a player having won three tricks continues to play for a jink, and fails to win every trick, he scores nothing that hand. It is optional on the part of the player to run this risk for the chance of a jink.

It is sometimes agreed, but generally not, that the winner of a jink may claim a wheel-out-i. e., that he may start for the next game with the score he had previous to playing the hand that made the jink.

At twenty-five robbing is sometimes permitted with the king of trumps as well as with the ace, the latter taking precedence when both are dealt. This occasionally leads to exposure of the king, and is better omitted. When the king is empowered to rob, jinking is not allowed.

Twenty-five and forty-five are good partner games, and are often played with partners when only four meet. Spoil five is never played with partners.

The following hints to learners and laws are condensed by permission from 'The Pocket Guide to Spoil Five,' by "Cavendish" (De la Rue & Co.) :

The principal interest at spoil five consists, odd as it may sound, in spoiling the game. The effort of each player, if unable personally to win three tricks, should be to prevent any other player from doing so, by playing to thwart the one who seems most likely to succeed. The deal is an advantage, as the dealer is led up to, and he has a greater chance of robbing than any other player. The first leader should generally lead his worst card to throw the lead into another hand. It is considered good play to reserve strong cards until the third trick, and not to be too eager to secure the first or second. Holding two or three cards of a suit not trumps, generally lead the lowest of them. When not the leader, if you hold one trump that cannot renege, generally trump with it. But, with two trumps, pass any but a winning card, reserving the trumps to spoil the strong hand. When last player, it is seldom right to refuse to win the trick, and never with a weak hand. By taking the trick you lessen the adversaries' chances, and your own, being nil, is not hurt. When holding one trump that can renege, and having no chance of the game yourself, retain the trump in your hand. It is almost certain to come in at the critical moment, spoiling the game, and keeping alive your interest in the pool. Trumps that cannot renege, if reserved, are liable to fall without effect to a trump lead. Never throw away a next best card of a suit not trumps; rather take the trick with a trump, and return the next best card. Rarely allow any player to make a second trick. The most unlikely man, to all appearance, often steps to the front, and secures a third trick and the pool.

The laws of spoil five vary in different localities. The following (or some other set) should be agreed to before commencing to play: :

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Shuffling. 1. Each player has a right to shuffle. Cutting. 2. At least four cards must be cut, and at least four left in the lower packet. 3. If a card is exposed in cutting, or in reuniting the packets after the cut, there must be a fresh cut. Dealing. 4. If there is a faced card in the pack, there must be a fresh deal, except the faced card happens to be the turn-up. 5. If there is a misdeal, the deal passes to the next player It is a misdeal, (a) if the dealer deals without having the pack cut; (b) if the dealer shuffles after the pack is cut with his consent; (e) if the dealer deals out of order-i. e., gives two cards where he should give three, or misses a hand, or exposes a card, or gives too few or too many cards to any player, even though the error is not discovered until the hand is played out (sometimes the dealer is allowed to deal again, on paying a second stake to the pool). 6. Each player is entitled to a deal-i. e., the game must not be abandoned except at the conclusion of a round, unless there is a spoil in the last deal of the round, when the dealer continues in order until a game is won. 7. If a player deals out of tun, he may be stopped at any time before the trump is turned. If not stopped the deal stands good, and the rotation of dealing proceeds to the dealer's left, as though he had dealt in turn. Playing. 8. If a player robs without the ace, or plays out of turn, or leads without awaiting the completion of the trick, or exposes a card, or omits to play to a trick, or revokes when not entitled, or reneges when not entitled, or plays to the first trick with too many or too few cards in hand, he forfeits the pool

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he cannot win the game that hand, and he cannot play again for that pool. (This is called hanging the hand. A severe penalty is necessary, because the faults here enumerated may be attended with serious consequences to the other players). Incorrect packs. 9. If a pack is discovered to be incorrect, redundant, or imperfect, the deal in which the discovery is made is void. All preceding deals stand good. SPRINGER [ARCH, E. C. S. col. 143].

SPRINKLER [ASPERSORIUM, E. C. S. col. 164].

SPRUCE BEER. Essence of spruce is obtained from the young shoots of the black spruce fir, by boiling and concentrating. Spruce beer is brewed from this essence, with the addition of water, sugar, and yeast, and flavoured with spices. The black beer of Dantzig is similarly made from the young shoots of another variety of fir; while a third kind forms an anti-scorbutic beer brewed for the Russian army.

SQUINTS [HAGIOSCOPE, E. C. S. col. 1215]. SS, COLLAR OF [COLLAR, E. C. S. col. 577]. STABAT MATER, or, to name it more fully after its first line, Stabat Mater dolorosa, is the title of a hymn or sequence, which, for its tender piety and pathos, has divided with the austere grandeur of the Dies Irae the admiration of the students of medieval hymnology. The Stabat Mater seems to have owed its suggestion to the text of the evangelist, "Now there stood by the cross of Jesus his mother" (St. John xix., 25); and it is sung in the service of the Romish Church on the day of the Commemoration of the Seven Dolours of the Blessed Virgin, and during Holy Week. The authorship of the Stabat Mater—which in different versions varies in length from ten to fourteen or fifteen six-line stanzas, as well as in the arrangement of its verses and the local occurrence of its phrases-is attributed to Pope Innocent III., by Pagi, in the life which he wrote of that Pontiff; otherwise there is hardly anything but unanimity in referring its production to Jacobus de Benedictis, or Jacopo de Benedetti, known more familiarly as Jacopone da Todi, from the name of his birthplace. He was a member of a noble family, and lived a secular life until the sudden death of his wife, in consequence of a fall from a scaffold, led him to devote himself to that which was accounted exclusively the religious life. Accordingly he entered the order of St. Francis, which was then (13th century) at its highest reputation for sanctity; and died in 1306, having written a large number of Italian spiritual songs and satires, in which he freely rebuked the vices of the priesthood, and suffered more than one imprisonment for his daring. Of his Latin poems scarcely more than two survive, of which the Stabat Mater, in spite of the distinctly Marian cultus which the latter part of it favours, presently acquired a reputation more than co-extensive with the author's communion. Various composers have written music for the Stabat Mater, as Palestrina, Pergolesi, and, more recently, Haydn, Neukomm, and Rossini.

(Daniel's Thesaurus Hymnologicus; Mone's Lateinische Hymnen ; Trench's Sacred Latin Poetry; Bässler's Auswahl Altchristlicher Lieder; and other sources.)

STACKING MACHINES [HORSE PITCHFORK, E. C. S.; THRESHING MACHINE, E. C. S.].

STAKTOMETER, or STALAGOMETER (from raλayμós, a drop), an arrangement described by Prof. Guthrie ('Proc. Roy. Soc.' xiii. p. 471, and Plate v. Fig. 7) for measuring the sizes of drops of liquids. A general description of it is given under DROP, E. C. S. col. 795.

STALLS, rows of fixed seats for the clergy ranged round the choirs of cathedral and collegiate churches or chapter-houses. In Italy they are usually of marble or stone, but elsewhere of wood. According to the size of the church, they comprise one or two rows of seats, divided from each other by projecting elbows. Each stall had a folding seat [MISERICORD, E. C. S. col. 1570], the back often richly carved, and overhead a canopy with pinnacles and other ornaments. Stalls are mentioned in the 11th century, but they were only generally introduced in the 13th century; the clergy prior to their introduction always stood during the service, and the misericord was a compromise allowing them to rest without actually sitting down. The places of the clergy were allotted according to their rank, the chief dignitaries having the four corner seats. Most of our cathedrals and many of the larger parish churches contain fine examples of carved stalls in a more or less perfect condition. (See the engravings of the choir of Salisbury cathedral, and the interior of Henry VIII.'s chapel, Westminster, under GOTHIC ARCHITECTURE, E. C. vol. iv. cols. 441 and 447.)

The chief seat on the dais in old baronial halls was sometimes a stall. Within the last few years the term has been applied to the front rows of seats reserved in the pit and gallery of operahouses, theatres, and concert-rooms.

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Fire insurance duties were repealed in 1869.
STANCHIONS (French, etançon), in Gothic architecture, the
upright iron bars between the mullions of windows or screens.
They are mostly square, and when not inserted into the stone
at the top are often terminated with a fleur de lis or other
ornament. In naval architecture any upright bar or post used
as a support is called a stanchion.

STANDARD [BANNER, E. C. vol. i. col. 879]. STANDARDS DEPARTMENT. A comprehensive account is given, in WEIGHTS AND MEASURES, STANDARD [E. C. vol. viii. col. 833], of the imperial and authoritative standards by which weights and measures, for use in scientific and commercial matters, are tested and verified. Since the appearance of that article a new governmental department has been established, for the care and management of these standards.

A scientific committee, comprising the Astronomer Royal, Sir J. F. W. Herschel, Sir J. W. Lubbock, General Sabine, the Master of the Mint, Professor W. H. Miller, and three other eminent men, was appointed in 1864, "to examine into the state of the Parliamentary Standard of Weight, and other circumstances affecting the Preservation and Use of the Standard." The committee ascertained the actual condition of the standard named, and also of many others; the arrangement of the boxes and cases in which they were inclosed; and the fitness of the rooms in which they were deposited. The committee reported on these matters, and pointed out the great want of some system for periodically verifying the weights and measures in use in the United Kingdom. They insisted on the necessity for the duty being placed under some one responsible person, in a department substantively distinct from the Exchequer. A similar recommendation had been made by scientific committees in 1841, 1854, and 1859, but had not been acted upon. In the autumn of 1864, the Exchequer department gave effect to many minor recommendations made by the committee; and in 1866 an act of parliament was passed (29 & 30 Vict. c. 82) authorizing the formation of a Standards Department, which was required to report its proceedings annually to parliament.

This new department was placed under the Board of Trade, instead of the Exchequer; but Mr. Chisholm, chief clerk of the Exchequer, was appointed to the new office of Warden of the Standards. Assisted by other officers of the departinent, his duties were to comprise the care of the primary or imperial and parliamentary standards, and the supervision of all local standards of weights and measures throughout the kingdom; and to act in conjunction with the local inspectors of weights and measures. The standard trial-pieces for the coinage were also placed under his charge. Gas meters or measures, by virtue of a special act of parliament, must accord with an official standard, which was among those entrusted to the warden. Until 1859 there was no legal provision for the official reverification of local standards. A statute of that year enacted that no copies of standard weights should be declared legal unless compared and reverified once in five years, or standard measures once in ten years. This statute was, however, imperfectly carried out; nearly one-half of the local standards remained unverified down to 1866; and no convictions under the weights and measures laws could be sustained when these defective standards were the only kinds that could be appealed to.

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the makers or agents. The old Norman Jewel-house, close to Westminster Abbey, and nearly fire-proof, was selected as the depository for the greater number of the official standards; while the all-important imperial standard pound and yard, the primary standard of weights and measures for the whole kingdom, were placed in a strong room in the basement of the building, in an iron safe made for the purpose by Messrs. Chubb.

The annual reports down to 1872 show a great advance in all the operations of the department. The number of official standards deposited is constantly increasing. They now comprise sixteen denominations of avoirdupois weight, fifteen of troy weight, two of postal weight (3 oz. and oz., for colonial use), thirty of bullion weight, four of gold-coin weight, nine of silver-coin weight, three of bronze-coin weight, twenty-three of decimal grain weight, eleven of line measures, forty-two capacity measures of various kinds, and seven of gas measures. Tables are printed in the reports, of the amount of error that may be allowed in the deviation of local standards from official standards, such allowance being in all cases very small in amount. The year's work in 1871, in verifying and re-verifying local standards, is thus classified :

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The chief verification of local standard gas-measures took place in 1862, consequent on the provisions of a new gas act. In 1871, 433 of the standards verified for the first time were substitutes for old standards worn out or lost.

STAR OF INDIA, ORDER OF THE. "The most exalted Order of the Star of India" was instituted by her majesty queen Victoria, in June 1861, as a means of marking her sense of conspicuous loyalty and merit, and conferring "high honour on the princes, chiefs, and people of her Indian empire," and on naval, military, and civil officers who may have rendered eminent service in India. The order consists of the sovereign, a grand master, who is always the governor general of India for the time being, and 25 knights, with such honorary knights as the sovereign may nominate. The insignia, comprising a collar, badge, and star of diamonds, has already been described [COLLAR, E. C. S. col. 578]. The motto is "Heaven's Light our Guide."

STARS. The most important addition to our knowledge of the stars in recent times has been derived from the application of the spectroscope to the observation of the heavenly bodies. It is to Huggins and Miller that we owe the earliest researches in this branch of inquiry. In 1864 they instituted an extensive series of experiments having for their object a comparison of the spectra of some of the principal fixed stars with the corre sponding spectra exhibited by certain terrestrial elements. It was established by their researches that many of the stars resemble the sun in so far as relates to the materials of which they are composed. Thus in Aldebaran there were discovered indications of hydrogen, sodium, magnesium, calcium, iron, bismuth, tellurium, antimony, and mercury. In Sirius the elements found to exist were sodium, magnesium, iron, and hydrogen. The spectrum of a Lyra or Vega exhibited traces of sodium, magnesium, and iron; and similarly in regard to a number of other stars which were examined.

Mr. Huggins has applied the principles of spectrum analysis to an explanation of the colours of stars. It is a matter of palpable observation that all stars are not of the same colour. While Sirius is plainly a white star, Aldebaran is decidedly red, and a Lyræ again has a bluish tinge. Now since all the stars may be regarded as suns, and since we have reason to One important work performed by the warden (in which he suppose the sun of our own system to be a solid or liquid incanwas assisted by a scientific committee) was to compare the offi- descent body, it is probable that the colour of the light which cial standards of avoirdupois and troy weight with the imperial emanates originally from the stars is white. We may, therepound. Sixteen of the former (from 56 lb. down to drachm) fore, regard the peculiar colour of a star to be attributable to and fifteen of the latter (from 1 lb. down to 1 grain) were thus some absorption which the light of the star undergoes subsecompared, with all the accuracy which scientific resources could quently to emission. Now when we consider the dark lines in ensure. In the warden's second Annual Report, for 1867-8, he the spectrum of a star it is clear that the colours in which those stated that arrangements had been completed for stamping every lines abound more will produce a less intense effect upon the verified local standard, registering it with the same stamp-eye than the colours which are less broken up by such lines. number, and thus preserving its identity; and also for recording In the case wherein the dark lines are faint and pretty uniformly the exact errors of rejected standards, and notifying these errors to distributed over the spectrum of the star, the combined effect

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will not be sensible, and the star will retain its original whiteness. Sirius is a striking instance of stars of this class. The spectrum of this star exhibits a great number of fine dark lines distributed throughout its entire extent, but they fail to produce a sensible effect, and the result is that the star, notwithstanding the existence of such absorption lines, continues to shine by a brilliant white light. On the other hand, if we consider the spectrum of a Herculis we encounter a totally different state of things. We perceive strongly marked groups of dark lines in the red, the green, and the blue of the spectrum; while again in the orange and yellow the indications of absorption are very faint. The result is, that the light of the star has a decidedly orange tinge. It would appear, then, that the peculiar colour of a star is attributable to the existence of vaporous substances in its atmosphere, which absorb rays of light of the same refrangibility as those which they emit.

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2. Yellow Stars. The spectra of the stars of this type are intermixed by numerous fine lines. Pollux, Capella, a Aquila, and the Sun are included in this class of stars.

3. Red and Orange Stars. The spectrum in this instance consists of eight or ten groups of alternate dark and bright lines, increasing in intensity towards the red; a Orionis, a Herculis, and 8 Pegasi are stars of this class.

4. Small red stars. The characteristic spectrum here consists of three bright lines increasing in intensity towards the violet. Out of 316 stars examined by Secchi, it was found that 164 belonged to the first class, and 140 to the second; while the remaining few were included in the third and fourth classes. STARVATION [ABSTINENCE, E. C. vol. i. col. 24; FASTING, E. C. S. col. 967].

By means of the principles of spectrum analysis the astronomer has been enabled to determine the velocity with which a star is approaching to, or receding from, the earth. If it be approaching the earth the number of vibrations of the light ether which meet the eye in a finite interval of time is greater than what it would be if the star had been stationary. The result will be that each colour will rise in the scale of the spectrum; in other words, it will deviate towards the violet. On the other hand, if the star be receding from the earth, the number of vibrations will be less, and a depression of each colour in the scale of the spectrum will ensue, or in other words it will incline towards the red. Huggins has successfully applied this principle to determine the velocity with which a star is approaching to, or receding from, the earth. His re-matical Analysis to the Theories of Electricity and Magnetism,' searches were originally based upon the spectrum of Sirius. By careful measurement he found that the line F in the spectrum of the star, indicative of hydrogen, deviated towards the red as compared with the position of the terrestrial hydrogen line. It followed, therefore, that Sirius is receding from the earth. Taking into account the amount of displacement of the hydrogen line, Huggins found the recession to be 414 miles in a second. This result, however, is independent of the annual motion of the earth, and of the proper motion in space of the solar system. Taking these two movements into account it is found that the velocity with which Sirius is receding relatively to the earth amounts to about 26 miles in a second.

The researches of Huggins here referred to were published in 1868. In 1872 he communicated to the Royal Society an account of further researches on the same subject obtained with more powerful means of spectroscopic observation. In this instance the spectra of several of the principal fixed stars, in addition to Sirius, were subjected to a careful scrutiny and some very interesting results were arrived at. With respect to Sirius the conclusion previously arrived at by Huggins respecting the movement of the star from the earth was fully confirmed by his more recent researches. In the latter instance, however, he estimates the velocity of the star to be between 18 and 22 miles per second. The following are the results he obtained in regard to some of the other stars examined by him.

a Orionis. This star was found to be receding from the earth (supposed also in motion) with a velocity of 29 miles in a

second.

Rigel. This star also appears to be receding from the earth. The velocity of recession Huggins estimates at 15 miles per second, taking into account the combined movements of the

earth and star.

Arcturus. This star appears to be approaching the earth. The velocity of its real movement was found to be 50 miles per second. Taking into account, however, the motion of the earth, and transferring it in the opposite direction to the star, it was found that the velocity of the relative approach of the star to the earth amounts to 55 miles per second.

Pollux. This star was also ascertained to be approaching the earth. The researches in this instance were founded upon an observed displacement of the three magnesium lines of the spectrum of the star. They indicated a velocity of relative approach amounting to 49 miles per second.

Secchi has devoted much attention to the spectroscopic observations of the stars, and has in many instances arrived at very interesting results. He considers that the stars in general are reducible to four distinct types, depending upon the peculiarities of their spectra. These are:

1. White Stars. These consist of stars such as Sirius, a Aquilæ, &c. Their spectra are distinguished by four groups of dark lines representing hydrogen.

ARTS AND SCI. DIV,—SUP.

STATICAL ELECTRICITY, a term sometimes applied to common or frictional electricity to distinguish it from current or voltaic electricity, and also from electro-dynamics. STATICAL ELECTRICITY, MATHEMATICAL THEORY OF. The mathematical theory of electricity is usually said to date from Poisson's Memoirs' on Two Spheres, to which electricity has been communicated, and which mutually influence each other. The electrical arrangement has thus been shown to depend upon a certain quantity, the nature of which will be explained in this article, called a potential, and this potential is found as the solution of a remarkable functional equation, considered by Poisson in these Memoirs. These researches were published in 1811, but a new aspect was communicated to the theory of electricity by a celebrated Memoir of Green, entitled An Essay on the application of Matheprinted about 1828, but which for many years was almost unnoticed either in this country or on the Continent. This paper contains a series of theorems on Attraction, some of which we hope to give in this article, and which Green has applied to very many phenomena connected with electricity and magnetism. About fifteen years afterwards the most important of the fundamental theorems were discovered independently by Gauss, in Germany, Chasles in France, and Sir W. Thomson in this country. Soon after this the memoir of Green became known, and was published in 'Crelle's Journal.' Since then the theorems on Attraction of Spheroids, which we have endeavoured to explain in an article on Magnetism [MAGNETISM, MATHEMATICAL THEORY OF, E. C. S. col. 1501], in which Laplace's coefficients are applied to ellipsoids of rotation generally, have been introduced into the theory of electricity by Lipschitz in the fifty-eighth volume of 'Crelle's Journal. In this memoir will be found some remarkable theorems relative to Laplace's equation.

We conclude this article by introducing Sir W. Thomson's investigations relative to the fundamental theorems already mentioned, as these investigations possess special interest. We shall assume the reader to be acquainted with so much of the theory as is contained in 'Murphy's Electricity.' Let x, y, z, be the coordinates of the attracted particle, x', y', z', the coordinates of the attracting particle, p' the electrical density p' dx' dy dz where is the distance beдам at x', y', ': then, if tween x, y, z, and x, y, z; and the integral comprises every particle of the electrified mass under consideration, then this integral, which we shall call V, is denominated the potential function of the system.

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The reader is supposed to know that when the point xyz is without the attracting body

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where U", as before, is the value of U, at the point where V becomes infinite.

We shall call, adopting Green's language, those points in which U, V, or their differential coefficients, become infinite, singular values of those functions, we shall also call the preceding, the fundamental equation. Now let pdo be the quantity of electricity on any element of a surface, whose co-ordinates are , n, C. Let x, y, z, be the co-ordinates of any point within the body bounded by this surface, x, y, z', the co-ordinates of any point outside the surface.

Let V. be the potential function for an exterior point, V, for an interior point, so that according to our definition we have: ρασ (n-y)2 + ράσ

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also let V., V, be the values which these functions have at the surface. Then putting in the fundamental equation U when (r) is the distance of an interior point x, y, z, from do, also putting V-V,, we have, since U has only one singular point (x, y, z) and 8V=0, 8

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- fde dy dz V 8U; but since, U and where du' is measured into the exterior space, and is therefore

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equal and contrary to dw, so that

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which will give V, and V, as the two potential functions within and without the surface, and Green has shown that there is only one value of p which can do this.

Now suppose a unit of positive electricity concentrated at a point in a conducting body in communication with the earth; then the potential function at the surface, will be zero, in consequence of the connection of the body with the earth, and within the surface equal to for points indefinitely near the point at which the electricity is concentrated. Hence we have proved from purely physical considerations that there is a

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