[1] Throughout this article, well-known names of persons and places
appear in their most familiar forms, generally without accents or
other diacritical signs. For the sake of homogeneity the articles on
these persons or places are also given under these forms, but in such
cases, the exact forms, according to the system of transliteration
adopted, are there given in addition.
[2] See Noldeke, _Beitrage zur Kenntniss der Poesie der alten Araber_
(1864), pp. 89 seq.
[3] De Goeje, _Memoires d'hist. et de geog. orient._ No. 2 (2nd ed.,
Leiden, 1864); Noldeke, _D.M.Z._, 1875, p. 76 sqq.; Baladhuri 137.
[4] The accounts differ; see Baladhuri 305. The chronology of the
conquests is in many points uncertain.
[5] Baladhuri 315 sq.; Tabari. i. 1068.
[6] He sought to make the whole nation a great host of God; the Arabs
were to be soldiers and nothing else. They were forbidden to acquire
landed estates in the conquered countries; all land was either made
state property or was restored to the old owners subject to a
perpetual tribute which provided pay on a splendid scale for the
army.
[7] Noldeke, _Tabari_, 246. To Omar is due also the establishment of
the Era of the Flight (Hegira).
[8] Even in the list of the slain at the battle of Honain the
Emigrants are enumerated along with the Meccans and Koreish, and
distinguished from the men of Medina.
[9] It was the same opposition of the spiritual to the secular
nobility that afterwards showed itself in the revolt of the sacred
cities against the Omayyads. The movement triumphed with the
elevation of the Abbasids to the throne. But, that the spiritual
nobility was fighting not for principle but for personal advantage
was as apparent in Ali's hostilities against Zobair and Talha, as in
that of the Abbasids against the followers af Ali.
[10] Or, at least, so they thought. The history of the letter to
'Abdallah b. abi Sarh seems to have been a trick played on the
caliph, who suspected Ali of having had a hand in it.
[11] Ma'ad is in the genealogical system the father of the Modar and
the Rab'ia tribes. Qais is the principal branch of the Modar.
[12] The Arabs always call them Rum, i.e. Romans.
[13] A single genealogist, Abu Yaqazan, says that he was a legitimate
son of Abu Sofian, and that his mother was Asma, daughter of A'war.
But all others call his mother Somayya, who is said to have been a
slave-girl of Hind, the wife of Abu Sofian, and who became later also
the mother of Abu Bakra. We cannot make out whether Abu Sofian
acknowledged him as his son or not. At a later period, the Abbasid
caliph Mahdi had the names of Ziyad and his descendants struck off
the rolls of the Koreish; but, after his death, the persons concerned
gained over the chief of the rolls office, and had their names
replaced in the lists (see Tabari iii. 479).
[14] Aghani xx. p. 13, Ibn abi Osaibia i. p. 118.
[15] Tabari ii. p. 82.
[16] See Chodzko, _Theatre persan_ (Paris, 1878).
[17] Dozy took _communis_ for a gloss to _civiliter_
[18] Formerly the capital of the homonymous province of Syria; it
lies a day's march west from Haleb (Aleppo).
[19] This account of the conquest is based partly on the researches
of Dozy, but mainly on those of Saavedra in his _Estudio sobre la
Invasion de los Arabes en Espana_ (Madrid, 1892). Some of the
details, however, e.g. the battle near Tamames and the part played by
the sons of Witiza, are based, not on documentary evidence, but on
probable inferences. For other accounts of the deaths of Musa and
Abdalaziz see Sir Wm. Muir, _Caliphate_ (London, 1891), pp. 368-9.
[20] Solaiman is the Arabic form of Solomon. The prophecy is to be
found in the _Kitab al-Oyun_, p. 24; cf. Tabari ii. p. 1138.
[21] Seyid Ameer Ali, _A Critical Examination of the Life and
Teachings of Mahomet_, pp. 341-343.
[22] Cf. Van Vloten, _Recherches sur la domination arabe, le
Chiitisme et les croyances messianiques sous le Khalifat des
Omayades_ (Amsterdam, 1894), p. 63 seq.
[23] Cf. Wellhausen, _Die Kampfe der Araber mit den Rom. in der Zeit
der Umaijiden_ (Gottingen, 1901), p. 31.
[24] Bayan i. p. 42; Dozy, _Histoire des musulmans d'Espagne_, i. p.
246, names the place Bacdoura or Nafdoura, the Spanish chronist
Nauam.
[25] Dozy i. p. 268.
[26] Merwan has been nicknamed _al-Ja'di_ and _al-Himar_ (the Ass).
As more than one false interpretation of these names has been given,
it is not superfluous to cite here Qaisarani (ed. de Jong, p. 31),
who says on good authority that a certain al-Ja'd b. Durham, killed
under the reign of Hisham for heretical opinions, had followers in
Mesopotamia, and that, when Merwan became caliph, the Khorasanians
called him a Ja'd, pretending that all'Ja'd had been his teacher. As
to al-Himar this was substituted also by the Khorasanians for his
usual title, al-Faras, "the race-horse."
[27] The Arabic word for "shedder of blood," _as-Saffah_, which by
that speech became a name of the caliph, designates the liberal host
who slaughters his camels for his guests. European scholars have
taken it unjustly in the sense of the bloodthirsty, and found in it
an allusion to the slaughter of the Omayyads and many others. At the
same time, it was not without much bloodshed that Abu'l-Abbas finally
established his power.
[28] The rule of the caliphs in Morocco, which had never been firmly
established, had already, in 740, given place to that of independent
princes (see MOROCCO, _History_).
[29] This Hashimiya near Kufa is not to be confused with that founded
by Abu'l-Abbas near Anbar.
[30] Cf. G. le Strange, _Baghdad during the Abbasid Caliphate_
(Oxford, 1900).
[31] Tabari iii. p. 443 seq.
[32] The first citizens of Medina who embraced Islam were called
Ansar ("helpers").
[33] On this event, see a remarkable essay by Barbier de Meynard in
the _Journal Asiatique_ for March-April, 1869.
[34] Cf. W.M. Patton, _Ahmed ibn Hanbal and the Mihna_ (Leiden,
1897); and article MAHOMMEDAN RELIGION.
[35] See M.J. de Goeje, _Memoire sur les migrations des Ziganes
travers l'Asie_ (Leiden, 1903); also GIPSIES.
[36] See M.J. de Goeje, "De legende der Zevenslapers van Efeze,"
_Versl. en Meded. der K. Akad. v. Wetensch. Afd. Letterk._ 4^e Reeks,
iii., 1900.
[37] See M.J. de Goeje, "De muur van Gog en Magog," _Versl. en
Meded._ 3^e Reeks, v., 1888.
[38] "Dinars" in the text of Tabari iii. 1685, must be an error for
"dirhems."
[39] This Bogha was called al-Kabir, or major; the ally of Wasif, a
man of much inferior consideration, al-Saghir, or minor.
[40] See Noldeke, _Orientalische Skizzen_, pp. 155 seq.
[41] For the connexion between Carmathians and Fatimites see under
FATIMITES.
[42] M.J. de Goeje, _Memoire sur les Carmathes du Bahrain et les
Fatimides_ (Leiden, 1886).
[43] See Defremery, _Memoire sur les Emirs al-Omara_ (Paris, 1848).
[44] Henceforward the history of the Caliphate is largely that of the
Seljuk princes (see SELJUKS).
CALIVER, a firearm used in the 16th century. The word is an English
corruption of "calibre," and arises from the "arquebus of calibre," that
is, of standard bore, which replaced the older arquebus. "Caliver,"
therefore, is practically synonymous with "arquebus." The heavier
musket, fired from a rest, replaced the caliver or arquebus towards the
close of the century.
CALIXTUS, or CALLISTUS, the name of three popes.
CALIXTUS I., pope from 217 to 222, was little known before the discovery
of the book of the _Philosophumena_. From this work, which is in part a
pamphlet directed against him, we learn that Calixtus was originally a
slave and engaged in banking. Falling on evil times, he was brought into
collision with the Jews, who denounced him as a Christian and procured
his exile to Sardinia. On his return from exile he was pensioned by Pope
Victor, and, later, was associated by Pope Zephyrinus in the government
of the Roman church. On the death of Zephyrinus (217) he was elected in
his place and occupied the papal chair for five years. His theological
adversary Hippolytus, the author of the _Philosophumena_, accused him of
having favoured the medalist or Patripassian doctrines both before and
after his election. Calixtus, however, condemned Sabellius, the most
prominent champion of that system. Hippolytus accused him also of
certain relaxations of discipline. It appears that Calixtus reduced the
penitential severities applied until his time to those guilty of
adultery and other analogous sins. Under Calixtus and his two immediate
successors, Hippolytus was the leader of a schismatic group, organized
by way of protest against the election of Calixtus. Calixtus died in
222, in circumstances obscured by legends. In the time of Constantine
the Roman church reckoned him officially among the martyr popes.
(L. D.*)
CALIXTUS II. (d. 1124), pope from 1119 to 1124, was Guido, a member of a
noble Burgundian family, who became archbishop of Vienne about 1088, and
belonged to the party which favoured reform in the Church. In September
1112, after Pope Paschal II. had made a surrender to the emperor Henry
V., Guido called a council at Vienne, which declared against lay
investiture, and excommunicated Henry. In February 1119 he was chosen
pope at Cluny in succession to Gelasius II., and in opposition to the
anti-pope Gregory VIII., who was in Rome. Soon after his consecration he
opened negotiations with the emperor with a view to settling the dispute
over investiture. Terms of peace were arranged, but at the last moment
difficulties arose and the treaty was abandoned; and in October 1119
both emperor and anti-pope were excommunicated at a synod held at Reims.
The journey of Calixtus to Rome early in 1120 was a triumphal march. He
was received with great enthusiasm in the city, while Gregory, having
fled to Sutri, was delivered into his hands and treated with great
ignominy. Through the efforts of some German princes negotiations
between pope and emperor were renewed, and the important Concordat of
Worms made in September 1122 was the result. This treaty, made possible
by concessions on either side, settled the investiture controversy, and
was confirmed by the Lateran council of March 1123. During his short
reign Calixtus strengthened the authority of the papacy in southern
Italy by military expeditions, and restored several buildings within the
city of Rome. During preparations for a crusade he died in Rome on the
13th or 14th of December 1124.
See M. Maurer, _Pabst Calixt II._ (Munich, 1889); U. Robert, _Hisloire
du pape Calixte II._ (Paris, 1891); and A. Hauck's _Realencyklopadie_,
Band iii. (Leipzig, 1897).
CALIXTUS III. (_c._1378-1458), pope from 1455 to 1458, was a Spaniard
named Alphonso de Borgia, or Borja. A native of Xativa, he gained a
great reputation as a jurist, becoming professor at Lerida; in 1429 he
was made bishop of Valencia, and in 1444 a cardinal, owing his promotion
mainly to his close friendship with Alphonso V., king of Aragon and
Sicily. Chosen pope in April 1455, he was very anxious to organize a
crusade against the Turks, and having sold many of his possessions,
succeeded in equipping a fleet. Neither the princes nor the people of
Europe, however, were enthusiastic in this cause, and very little result
came from the pope's exertions. During his papacy Calixtus became
involved in a quarrel with his former friend, Alphonso of Aragon, now
also king of Naples, and after the king's death in June 1458 he refused
to recognize his illegitimate son, Ferdinand, as king of Naples,
asserting that this kingdom was a fief of the Holy See. This pope was
notorious for nepotism, and was responsible for introducing his nephew,
Rodrigo Borgia, afterwards Pope Alexander VI., to Rome. He died on the
6th of August 1458.
See A. Hauck's _Realencyklopadie_, Band iii. (Leipzig, 1897).
CALIXTUS, GEORG (1586-1656), Lutheran divine, was born at Medelby, a
village of Schleswig, in 1586. After studying philology, philosophy and
theology at Helmstadt, Jena, Giessen, Tubingen and Heidelberg, he
travelled through Holland, France and England, where he became
acquainted with the leading Reformers. On his return in 1614 he was
appointed professor of theology at Helmstadt by the duke of Brunswick,
who had admired the ability he displayed when a young man in a dispute
with the Jesuit Augustine Turrianus. In 1613 he published a book,
_Disputationes de Praecipuis Religionis Christianae Capitibus_, which
provoked the hostile criticism of orthodox scholars; in 1619 he
published his _Epitome theologiae_, and some years later his _Theologia
Moralis_ (1634) and _De Arte Nova Nihusii_. Roman Catholics felt them to
be aimed at their own system, but they gave so great offence to
Lutherans as to induce Statius Buscher to charge the author with a
secret leaning to Romanism. Scarcely had he refuted the accusation of
Buscher, when, on account of his intimacy with the Reformed divines at
the conference of Thorn (1645), and his desire to effect a
reconciliation between them and the Lutherans, a new charge was
preferred against him, principally at the instance of Abraham Calovius
(1612-1686), of a secret attachment to Calvinism. In fact, the great aim
of his life was to reconcile Christendom by removing all unimportant
differences. The disputes to which this attitude gave rise, known in the
Church as the Syncretistic controversy, lasted during the whole lifetime
of Calixtus, and distracted the Lutheran church, till a new controversy
arose with P.J. Spener and the Pietists of Halle. Calixtus died in 1656.
There is a monograph on Calixtus by E.L.T. Henke (2 vols., 1853-1856);
see also Isaak Dorner, _Gesch. d. protest. Theol._ pp. 606-624; and
especially Herzog-Hauck, _Realencyklopadie_.
CALL (from Anglo-Saxon _ceallian_, a common Teutonic word, cf. Dutch
_kallen_, to talk or chatter), to speak in a loud voice, and
particularly to attract some one's attention by a loud utterance. Hence
its use for a visit at a house, where the name of the occupier, to whom
the visit was made, was called aloud, in early times, to indicate the
presence of the visitor. It is thus transferred to a short stay at a
place, but usually with the idea of a specific purpose, as in "port of
call," where ships stop in passing. Connected with the idea of summoning
by name are such uses as "roll-call" or "call-over," where names are
called over and answered by those present; similar uses are the "call to
the bar," the summoning at an Inn of Court of those students qualified
to practise as barristers, and the "call within the bar" to the
appointment of king's counsel. In the first case the "bar" is that which
separates the benchers from the rest of the body of members of the Inn,
in the other the place in a court of law within which only king's
counsel, and formerly serjeants-at-law, are allowed to plead. "Call" is
also used with a particular reference to a divine summons, as of the
calling of the apostles. It is thus used in nonconformist churches of
the invitation to serve as minister a particular congregation or chapel.
It is from this sense of a _vocatio_ or summons that the word "calling"
is used, not only of the divine vocation, but of a man's ordinary
profession, occupation or business. In card games "call" is used, in
poker, of the demand that the hand of the highest bettor be exposed or
seen, exercised by that player who equals his bet; in whist or bridge,
of a certain method of play, the "call" for a suit or for trumps on the
part of one partner, to which the other is expected to respond; and in
many card games for the naming of a card, irregularly exposed, which is
laid face up on the table, and may be thus "called" for, at any point
the opponent may choose.
"Call" is also a term on the English and American stock exchanges for a
contract by which, in consideration of a certain sum, an "option" is
given by the person making or signing the agreement to another named
therein or his order or to bearer, to "call" for a specified amount of
stock at a certain day for a certain price. A "put," which is the
reverse of a "call," is the option of selling (putting) stock at a
certain day for a certain price. A combined option of either calling or
putting is termed a "straddle," and sometimes on the American stock
exchange a "spread-eagle." (See further STOCK EXCHANGE.) The word is
also used, in connexion with joint-stock companies, to signify a demand
for instalments due on shares, when the capital of the company has not
been demanded or "called" up at once. (See COMPANY.)
CALLANDER, a police burgh of Perthshire, Scotland, 16 m. north-west of
Stirling by the Caledonian railway. Pop. (1901) 1458. Situated on the
north bank of the Teith, here crossed by a three-arched bridge, and
sheltered by a ridge of wooded hills, it is in growing repute as a
health resort. A mile and a half north-east are the Falls of Bracklinn
(Gaelic, "white-foaming pool"), formed by the Keltie, which takes a leap
of 50 ft. down the red sandstone gorge on its way to the Teith. Two
miles north-west of Callander is the Pass of Leny, "the gate of the
Highlands," and farther in the same direction is Loch Lubnaig, on the
shores of which stand the ruins of St Bride's chapel. Callander owes
much of its prosperity to the fact that it is the centre from which the
Trossachs is usually visited, the route being that described in Scott's
_Lady of the Lake_. The ascent of Ben Ledi is commonly made from the
town.
CALLAO, a city, port and coast department of Peru, 8-1/2 m. west of
Lima, in 12 deg. 04' S., 77 deg. 13' W. Pop. (1905) 31,128, of whom 3349
were foreigners. The department includes the city and its environs,
Bellavista and La Punta, and the neighbouring islands, San Lorenzo,
Fronton, the Palominos, &c., and covers an area of 14-1/2 sq. m. Callao
is the principal port of the republic, its harbour being a large bay
sheltered by a tongue of land on the south called La Punta, and by the
islands of San Lorenzo and Fronton. The anchorage is good and safe, and
the harbour is one of the best on the Pacific coast of South America.
The city stands on the south side of the bay, and is built on a flat
point of land only 8 ft. above sea-level. The houses are for the most
part low and cheaply built, and the streets are narrow, badly paved,
irregular and dirty. The climate is good and the coast is swept by cool
ocean breezes, the average temperatures ranging from 65 deg. to 77 deg.
F., but notwithstanding this, Callao has a bad reputation for fevers and
contagious diseases, chiefly because of its insanitary condition. Its
noteworthy public buildings are the custom-house and its storehouses
which occupy the old quadrangular fortress built by the Spanish
government between 1770 and 1775, and cover 15 acres, the prefecture,
the military and naval offices and barracks, the post-office, three
Catholic churches, a hospital, market, three clubs and some modern
commercial houses. The present city is half a mile north of the site of
the old town, which was destroyed by an earthquake and tidal wave in
1746. For a short time the commercial interests of the stricken city
centred at Bellavista, 1-1/4 m. east, where wheat granaries were built
and still remain, but later the greater convenience of a waterside site
drew the merchants and population back to the vicinity of the submerged
town. The importance of Callao in colonial times, when it was the only
open port south of Panama, did not continue under the new political
order, because of the unsettled state of public affairs and the loss of
its monopoly. This decline in its prosperity was checked, and the modern
development of the port began, when a railway was built from Callao into
the heart of the Andes, and Callao is now an important factor in the
development of copper-mining. The port is connected with Lima by two
railways and an electric tramway, with Oroya by railway 138 m. long, and
with Cerro de Pasco by railway 221 m. A short railway also runs from the
port to the Bellavista storehouses. The port is provided with modern
harbour improvements, consisting of sea-walls of concrete blocks, two
fine docks with berthing spaces for 30 large vessels, and a large
floating-dock (300 ft. long on the blocks and capable of receiving
vessels up to 21 ft. draught and 5000 tons weight), which was built in
Glasgow and was sent out to Callao in 1863. The docks are provided with
gas and electric lights, 18 steam cranes for loading and discharging
vessels, a triple line of railway and a supply of fresh water. Callao
was formerly the headquarters in South America of the Pacific Steam
Navigation Co., Ltd. (incorporated 1840), but Valparaiso now occupies
that position. There are, owing perhaps to the proximity of Lima, few
industrial establishments in the city; among them are a large sugar
refinery, some flour-mills, a brewery, a factory for making effervescent
drinks, and a number of foundries and repair shops. Being a port of the
first class, Callao is an important distributing centre for the coasting
trade, in which a large number of small vessels are engaged. The foreign
steamship companies making it a regular port of call are the Pacific
Steam Navigation Co. (British), the Compania Sud-America (Chilean), the
Kosmos and Roland lines (German), the Merchants line (New York), and a
Japanese line from the ports of Japan and China. A subsidized Peruvian
line is also contemplated to ply between the Pacific ports of South
America with an eventual extension of the service to Europe. The
arrivals from and clearances for foreign ports in 1907 were as
follows:--
Steamers. Sailing Vessels.
No. Tonnage. No. Tonnage.
Arrivals 518 937,302 924 174,165
Clearances 517 937,706 931 163,365
The exports from Callao are guano, sugar, cotton, wool, hides, silver,
copper, gold and forest products, and the imports include timber and
other building materials, cotton and other textiles, general merchandise
for personal, household and industrial uses, railway material, coal,
kerosene, wheat, flour and other food stuffs. The maintenance of peace
and order, and the mining development of the interior, have added to the
trade and prosperity of the port.
The history of Callao has been exceptionally eventful. It was founded in
1537, two years after Pizarro had founded Lima. As the port of that
capital and the only open port below Panama it grew rapidly in
importance and wealth. It was raised to the dignity of a city in 1671.
The appearance of Sir Francis Drake in the bay in 1578 led to the
fortification of the port, which proved strong enough to repel an attack
by the Dutch in 1624. The city was completely destroyed and partly
submerged by the great earthquake of the 28th of October 1746, in which
about 6000 persons perished. The new city was strongly fortified and
figured prominently in the struggle for independence, and also in the
various revolutions which have convulsed the republic. Its political
autonomy dates from 1836, when it was made a coast department. The
Callao fortifications were bombarded by a Spanish fleet under Admiral
Mendez Nunez on the 2nd of May 1866, when there were heavy losses both
in lives and material. Again, in 1880, the city was bombarded by the
Chileans, though it was almost defenceless, and fell into the possession
of the invaders after the capture of Lima in the following year. Before
the surrender all the Peruvian naval vessels in the harbour were sunk,
to prevent their falling into the possession of the enemy.
CALLCOTT, SIR AUGUSTUS WALL (1779-1844), English landscape painter, was
born at Kensington in 1779 and died there in 1844. His first study was
music; and he sang for several years in the choir of Westminster Abbey.
But at the age of twenty he had determined to give up music, and had
exhibited his first painting at the Royal Academy. He gradually rose to
distinction, and was elected an associate in 1807 and an academician in
1810. In 1827 he received the honour of knighthood; and, seven years
later, was appointed surveyor of the royal pictures. His two principal
subject pictures--"Raphael and the Fornarina," and "Milton dictating to
his Daughters," are much inferior to his landscapes, which are placed in
the highest class by their refined taste and quiet beauty.
His wife, MARIA, Lady Callcott (1786-1844), whom he married in 1827, was
a daughter of Admiral Dundas and widow of Captain Thomas Graham, R.N.
(d. 1822). With her first husband she travelled in India, South Africa
and South America, where she acted for some time as teacher of Donna
Maria, who became queen of Portugal in 1826; and in the company of her
second husband she spent much time in the south of Europe. She published
accounts of her visits to India (1812), and to the environs of Rome
(1820); _Memoirs of Poussin_ (1820); a _History of France_; a _History
of Spain_ (1828); _Essays toward a History of Painting_ (1836); _Little
Arthur's History of England_ (1836); and the _Scripture Herbal_ (1842).
CALLCOTT, JOHN WALL (1766-1821), English musician, brother of Sir
Augustus Callcott, was born at Kensington on the 20th of November 1766.
At the age of seven he was sent to a neighbouring day-school, where he
continued for five years, studying chiefly Latin and Greek. During this
time he frequently went to Kensington church, in the repairs of which
his father was employed, and the impression he received on hearing the
organ of that church seems to have roused his love for music. The
organist at that time was Henry Whitney, from whom Callcott received his
first musical instruction. He did not, however, choose music as a
profession, as he wished to become a surgeon. But on witnessing a
surgical operation he found his nervous system so seriously affected by
the sight, that he determined to devote himself to music. His intimacy
with Dr Arnold and other leading musicians of the day procured him
access to artistic circles; he was deputy organist at St George the
Martyr, Queen Square, Bloomsbury, from 1783 to 1785, in which year his
successful competition for three out of the four prize medals offered by
the "Catch Club" soon spread his reputation as composer of glees,
catches, canons and other pieces of concerted vocal music. The
compositions with which he won these medals were--the catch "O beauteous
fair," the canon "Blessed is he," and the glee "Dull repining sons of
care." In these and other similar compositions he displays considerable
skill and talent, and some of his glees retain their popularity at the
present day. In 1787 Callcott helped Dr Arnold and others to form the
"Glee Club." In 1789 he became one of the two organists at St Paul's,
Covent Garden, and from 1793 to 1802 he was organist to the Asylum for
Female Orphans. As an instrumental composer Callcott never succeeded,
not even after he had taken lessons from Haydn. But of far greater
importance than his compositions are his theoretical writings. His
_Musical Grammar_, published in 1806 (3rd ed., 1817), was long
considered the standard English work of musical instruction, and in
spite of its being antiquated when compared with modern standards, it
remains a scholarly and lucid treatment of the rudiments of the art.
Callcott was a much-esteemed teacher of music for many years. In 1800 he
took his degree of Mus.D. at Oxford, where fifteen years earlier he had
received his degree of bachelor of music, and in 1805 he succeeded Dr
Crotch as musical lecturer at the Royal Institution. Towards the end of
his life his artistic career was twice interrupted by the failure of his
mental powers. He died at Bristol after much suffering on the 15th of
May 1821. A posthumous collection of his most favourite vocal pieces was
published in 1824 with a memoir of his life by his son-in-law, William
Horsley, himself a composer of note.
Callcott's son, WILLIAM HUTCHINS CALLCOTT (1807-1882), inherited to a
large extent the musical gifts of his father. His song, "The last man,"
and his anthem, "Give peace in our time, O Lord," were his best-known
compositions.
CALLIAS, tyrant of Chalcis in Euboea. With the assistance of Philip II.
of Macedon, which he hoped to obtain, he contemplated the subjugation of
the whole island. But finding that Philip was unwilling to help him,
Callias had recourse to the Athenians, although he had previously (350
B.C.) been engaged in hostilities with them. With the support of
Demosthenes, he was enabled to conclude an alliance with Athens, and the
tribute formerly paid by Eretria and Oreus to Athens was handed over to
him. But his plan of uniting the whole of Euboea under his rule, with
Chalcis as capital, was frustrated by Philip, who set up tyrants chosen
by himself at Eretria and Oreus. Subsequently, when Philip's attention
was engaged upon Thrace, the Athenians in conjunction with Callias drove
out these tyrants, and Callias thus became master of the island
(Demosthenes, _De Pace_, p. 58; _Epistola Philippi_, p. 159; Diod. Sic.
xvi. 74). At the end of his life he appears to have lived at Athens, and
Demosthenes proposed to confer the citizenship upon him (Aeschines,
_Contra Ctesiphontem_, 85, 87).
CALLIAS and HIPPONICUS, two names borne alternately by the heads of a
wealthy and distinguished Athenian family. During the 5th and 4th
centuries B.C. the office of _daduchus_ or torch-bearer at the
Eleusinian mysteries was the hereditary privilege of the family till its
extinction. The following members deserve mention.
1. CALLIAS, the second of the name, fought at the battle of Marathon
(490) in priestly attire. Some time after the death of Cimon, probably
about 445 B.C., he was sent to Susa to conclude with Artaxerxes, king of
Persia, a treaty of peace afterwards misnamed the "peace of Cimon."
Cimon had nothing to do with it, and he was totally opposed to the idea
of peace with Persia (see CIMON). At all events Callias's mission does
not seem to have been successful; he was indicted for high treason on
his return to Athens and sentenced to a fine of fifty talents.
See Herodotus vii. 151; Diod. Sic. xii. 4; Demosthenes, _De Falsa
Legatione_, p. 428; Grote recognizes the treaty as a historical fact,
_History of Greece_, ch. xlv., while Curtius, bk. iii. ch. ii., denies
the conclusion of any formal treaty; see also Ed. Meyer,
_Forschungen_, ii.; J.B. Bury in _Hermathena_, xxiv. (1898).
2. HIPPONICUS, son of the above. Together with Eurymedon he commanded
the Athenian forces in the incursion into Boeotian territory (426 B.C.)
and was slain at the battle of Delium (424). His wife, whom he
divorced, subsequently became the wife of Pericles; one of his
daughters, Hipparete, married Alcibiades; another, the wife of
Theodorus, was the mother of the orator Isocrates.
See Thucydides iii. 91; Diod. Sic. xii. 65; Andocides, _Contra
Alcibiadem_, 13.
3. CALLIAS, son of the above, the black sheep of the family, was
notorious for his profligacy and extravagance, and was ridiculed by the
comic poets as an example of a degenerate Athenian (Aristophanes,
_Frogs_, 429, _Birds_, 283, and schol. Andocides, _De Mysteriis_,
110-131). The scene of Xenophon's _Symposium_ and Plato's _Protagoras_
was laid at his house. He was reduced to a state of absolute poverty
and, according to Aelian (_Var. Hist._ iv. 23), committed suicide, but
there is no confirmation of this. In spite of his dissipated life he
played a certain part in public affairs. In 392 he was in command of the
Athenian hoplites at Corinth, when the Spartans were defeated by
Iphicrates. In 371 he was at the head of the embassy sent to make terms
with Sparta. The peace which was the result was called after him the
"peace of Callias."
See Xenophon, _Hellenica_, iv. 5, vi. 3; and DELIAN LEAGUE.
CALLIMACHUS, an Athenian sculptor of the second half of the 5th century
B.C. Ancient critics associate him with Calamis, whose relative he may
have been. He is given credit for two inventions, the Corinthian column
and the running borer for drilling marble. The most certain facts in
regard to him are that he sculptured some dancing Laconian maidens, and
made a golden lamp for the Erechtheum (about 408 B.C.); and that he used
to spoil his works by over-refinement and excessive labour.
CALLIMACHUS, Greek poet and grammarian, a native of Cyrene and a
descendant of the illustrious house of the Battiadae, flourished about
250 B.C. He opened a school in the suburbs of Alexandria, and some of
the most distinguished grammarians and poets were his pupils. He was
subsequently appointed by Ptolemy Philadelphus chief librarian of the
Alexandrian library, which office he held till his death (about 240).
His _Pinakes_ (tablets), in 120 books, a critical and chronologically
arranged catalogue of the library, laid the foundation of a history of
Greek literature. According to Suidas, he wrote about 800 works, in
verse and prose; of these only six hymns, sixty-four epigrams and some
fragments are extant; a considerable fragment of the _Hecale_, an
idyllic epic, has also been discovered in the Rainer papyri (see Kenyon
in _Classical Review_, November 1893). His _Coma Berenices_ is only
known from the celebrated imitation of Catullus. His _Aitia_ (causes)
was a collection of elegiac poems in four books, dealing with the
foundation of cities, religious ceremonies and other customs. According
to Quintilian (_Instit._ x. i. 58) he was the chief of the elegiac
poets; his elegies were highly esteemed by the Romans, and imitated by
Ovid, Catullus and especially Propertius. The extant hymns are extremely
learned, and written in a laboured and artificial style. The epigrams,
some of the best specimens of their kind, have been incorporated in the
Greek Anthology. Art and learning are his chief characteristics,
unrelieved by any real poetic genius; in the words of Ovid (_Amores_, i.
15)--
"Quamvis ingenio non valet, arte valet."
EDITIONS.--Hymns, epigrams and fragments (the last collected by
Bentley) by J.A. Ernesti (1761), and O. Schneider (1870-1873) (with
elaborate indices and excursuses); hymns and epigrams, by A. Meineke
(1861), and U. Wilamowitz-Mollendorff (1897). See _Neue Bruchstucke
aus der Hekale des Kallimachus_, by T. Gomperz (1893); also G. Knaack,
_Callimachea_ (1896); A. Bertrami, _Gl' Inni di Callimacho e il Nomo
di Terpandro_ (1896); K. Kuiper, _Studia Callimachea_ (1896); A.
Hamette, _Les Epigrammes de Callimaque: etude critique et litteraire_
(Paris, 1907). There are English translations (verse) by W. Dodd
(1755) and H.W. Tytler (1793); (prose) by J. Banks (1856). See also
Sandys, _Hist. of Class. Schol._ i. (ed. 1906), p. 122.
CALLINUS of Ephesus, the oldest of the Greek elegiac poets and the
creator of the political and warlike elegy. He is supposed to have
flourished between the invasion of Asia Minor by the Cimmerii and their
expulsion by Alyattes (630-560 B.C.). During his lifetime his own
countrymen were also engaged in a life-and-death struggle with the
Magnesians. These two events give the key to his poetry, in which he
endeavours to rouse the indolent Ionians to a sense of patriotism. Only
scanty fiagments of his poems remain; the longest of these (preserved in
Stobaeus, _Florilegium_, li. 19) has even been ascribed to Tyrtaeus.
Edition of the fragments by N. Bach (1831), and in Bergk, _Poetae
Lyrici Graeci_ (1882). On the date of Callinus, see the histories of
Greek literature by Mure and Muller; G.H. Bode, _Geschichte der
hellenischen Dichtkunst_, ii. pt. i. (1838); and G. Geiger, _De
Callini Aetate_ (1877), who places him earlier, about 642.
CALLIOPE, the muse of epic poetry, so named from the sweetness of her
vioce (Gr. [Greek: kallos], beauty; [Greek: ops], voice). In Hesiod she
was the last of the nine sisters, but yet enjoyed a supremacy over the
others. (See also MUSES, THE.)
CALLIRRHOE, in Greek legend, second daughter of the river-god Achelous
and wife of Alcmaeon (q.v.). At her earnest request her husband induced
Phegeus, king of Psophis in Arcadia, and the father of his first wife
Arsinoe (or Alphesiboea), to hand over to him the necklace and peplus
(robe) of Harmonia (q.v.), that he might dedicate them at Delphi to
complete the cure of his madness. When Phegeus discovered that they were
really meant for Callirrhoe, he gave orders for Alcmaeon to be waylaid
and killed (Apollodorus iii. 7, 2. 5-7; Thucydides ii. 102). Callirrhoe
now implored the gods that her two young sons might grow to manhood at
once and avenge their father's death. This was granted, and her sons
Amphoterus and Acarnan slew Phegeus with his two sons, and returning
with the necklace and peplus dedicated them at Delphi (Ovid, _Metam._
ix. 413).
CALLISTHENES (_c._ 360-328 B.C.), of Olynthus, Greek historian, a
relative and pupil of Aristotle, through whose recommendation he was
appointed to attend Alexander the Great in his Asiatic expedition. He
censured Alexander's adoption of oriental customs, inveighing especially
against the servile ceremony of adoration. Having thereby greatly
offended the king, he was accused of being privy to a treasonable
conspiracy and thrown into prison, where he died from torture or
disease. His melancholy end was commemorated in a special treatise
([Greek: Kallisthenaes ae peri penthous]) by his friend Theophrastus,
whose acquaintance he made during a visit to Athens. Callisthenes wrote
an account of Alexander's expedition, a history of Greece from the peace
of Antalcidas (387) to the Phocian war (357), a history of the Phocian
war and other works, all of which have perished. The romantic life of
Alexander, the basis of all the Alexander legends of the middle ages,
originated during the time of the Ptolemies, but in its present form
belongs to the 3rd century A.D. Its author is usually known as
pseudo-Callisthenes, although, in the Latin translation by Julius
Valerius Alexander Polemius (beginning of the 4th century) it is
ascribed to a certain Aesopus; Aristotle, Antisthenes, Onesicritus and
Arrian have also been credited with the authorship. There are also
Syrian, Armenian and Slavonic versions, in addition to four Greek
versions (two in prose and two in verse) in the middle ages (see
Krumbacher, _Geschichte der byzantinischen Litteratur_, 1897, p. 849).
Valerius's translation was completely superseded by that of Leo,
arch-priest of Naples in the 10th century, the so-called _Historia de
Preliis_.
See _Scriptores rerum Alexandri Magni_ (by C.W. Muller, in the Didot
edition of Arrian, 1846), containing the genuine fragments and the
text of the pseudo-Callisthenes, with notes and introduction; A.
Westermann, _De Callisthene Olynthio et Pseudo-Callisthene
Commentatio_ (1838-1842); J. Zacher, _Pseudo-Callisthenes_ (1867); W.
Christ, _Geschichte der griechischen Litteratur_ (1898), pp. 363, 819;
article by Edward Meyer in Ersch and Gruber's _Allgemeine
Encyklopadie_; A. Ausfeld, _Zur Kritik des griechischen
Alexanderromans_ (Bruchsal, 1894); Plutarch, _Alexander_, 52-55;
Arrian, _Anab_. iv. 10-14; Diog. Laertius v. I; Quintus Curtius viii.
5-8; Suidas _s.v._ See also ALEXANDER THE GREAT (_ad fin._). For the
Latin translations see Teuffel-Schwabe, _Hist. of Roman Literature_
(Eng, trans.), S 399; and M. Schanz, _Geschichte der romischen
Litteratur_, iv. i., p. 43.
CALLISTO, in Greek mythology, an Arcadian nymph, daughter of Lycaon and
companion of Artemis. She was transformed into a bear as a penalty for
having borne to Zeus a son, Arcas, the ancestor of the Arcadians. Hera,
Zeus and Artemis are all mentioned as the authors of the transformation.
Arcas, when hunting, encountered the bear Callisto, and would have shot
her, had not Zeus with swift wind carried up both to the skies, where he
placed them as a constellation. In another version, she was slain by
Artemis. Callisto was originally only an epithet of the Arcadian Artemis
herself.
See Apollodorus iii. 8; Ovid, _Metam._ ii. 381-530; R. Franz, _De
Callistus fabula_ (1890), which deals exhaustively with the various
forms of the legend.
CALLISTRATUS, Alexandrian grammarian, flourished at the beginning of the
2nd century B.C. He was one of the pupils of Aristophanes of Byzantium,
who were distinctively called Aristophanei. Callistratus chiefly devoted
himself to the elucidation of the Greek poets; a few fragments of his
commentaries have been preserved in the various collections of scholia
and in Athenaeus. He was also the author of a miscellaneous work called
[Greek: Summikta] used by the later lexicographers, and of a treatise on
courtesans (Athenaeus iii. 125 B, xiii. 591 D). He is not to be confused
with Callistratus, the pupil and successor of Isocrates and author of a
history of Heraclea in Pontus.
See R. Schmidt, _De Callistrato Aristophaneo_, appended to A. Nauck's
_Aristophanis Byzantii Fragmenta_ (1848); also C.W. Muller, _Fragmenta
Historicorum Graecorum_, iv. p. 353 note.
CALLISTRATUS, an Athenian poet, only known as the author of a hymn in
honour of Harmodius (q.v.) and Aristogeiton. This ode, which is to be
found in Athenaeus (p. 695), has been beautifully translated by Thomas
Moore.
CALLISTRATUS, Greek sophist and rhetorician, probably flourished in the
3rd century. He wrote [Greek: Ekfraseis], descriptions of fourteen works
of art in stone or brass by distinguished artists. This little work,
which is written in a dry and affected style, without any real artistic
feeling, is usually edited with the [Greek: Eikones] of Philostratus.
Edition by Schenkl-Reisch (Teubner series, 1902); see also C.G. Heyne,
_Opuscula Academica_, v. pp. 196-221, with commentary on the
_Descriptiones_; F. Jacobs, _Animadversiones criticae in Callistrati
statuas_ (1797).
CALLISTRATUS of Aphidnae, Athenian orator and general in the 4th century
B.C. For many years, as _prostates_, he supported Spartan interests at
Athens. On account of the refusal of the Thebans to surrender Oropus,
which on his advice they had been allowed to occupy temporarily,
Callistratus, despite his magnificent defence (which so impressed
Demosthenes that he resolved to study oratory), was condemned to death,
361 B.C. He fled to Methone in Macedonia, and on his return to Athens in
355 he was executed.
See Xenophon, _Hellenica_, iii. 3, vi. 2; Lycurgus, _In Leocr._ 93.
CALLOT, JACQUES (1592-1635), French engraver, was born at Nancy in
Lorraine, where his father, Jean Callot, was a herald-at-arms. He early
discovered a very strong predilection for art, and at the age of twelve
quitted home without his father's consent, and set out for Rome where he
intended to prosecute his studies. Being utterly destitute of funds he
joined a troop of Bohemians, and arrived in their company at Florence.
In this city he had the good fortune to attract the notice of a
gentleman of the court, who supplied him with the means of study; but he
removed in a short time to Rome, where, however, he was recognized by
some relatives, who immediately compelled him to return home. Two years
after this, and when only fourteen years old, he again left France
contrary to the wishes of his friends, and reached Turin before he was
overtaken by his elder brother, who had been despatched in quest of him.
As his enthusiasm for art remained undiminished after these
disappointments, he was at last allowed to accompany the duke of
Lorraine's envoy to the papal court. His first care was to study the art
of design, of which in a short time he became a perfect master. Philip
Thomasin instructed him in the use of the graver, which, however, he
ultimately abandoned, substituting the point as better adapted for his
purposes. From Rome he went to Florence, where he remained till the
death of Cosimo II., the Maecenas of these times. On returning to his
native country he was warmly received by the then duke of Lorraine, who
admired and encouraged him. As his fame was now spread abroad in various
countries of Europe, many distinguished persons gave him commissions to
execute. By the Infanta Isabella, sovereign of the Low Countries, he was
commissioned to engrave a design of the siege of Breda; and at the
request of Louis XIII. he designed the siege of Rochelle and the attack
on the Isle of Re. When, however, in 1631 he was desired by that
monarch to execute an engraving of the siege of Nancy, which he had just
taken, Callot refused, saying, "I would rather cut off my thumb than do
anything against the honour of my prince and of my country"; to which
Louis replied that the duke of Lorraine was happy in possessing such
subjects as Callot. Shortly after this he returned to his native place,
from which the king failed to allure him with the offer of a handsome
pension. He engraved in all about 1600 pieces, the best of which are
those executed in aquafortis. No one ever possessed in a higher degree
the talent for grouping a large number of figures in a small space, and
of representing with two or three bold strokes the expression, action
and peculiar features of each individual. Freedom, variety and _naivete_
characterize all his pieces. His Fairs, his Miseries of War, his Sieges,
his Temptation of St Anthony and his Conversion of St Paul are the
best-known of his plates.
See also Edouard Meaume, _Recherches sur la vie de Jacques Callot_
(1860).
CALLOVIAN (from _Callovium_, the Latinized form of Kellaways, a village
not far from Chippenham in Wiltshire), in geology, the name introduced
by d'Orbigny for the strata which constitute the base of the Oxfordian
or lowermost stage of the Middle Oolites. The term used by d'Orbigny in
1844 was "Kellovien," subsequently altered to "Callovien" in 1849;
William Smith wrote "Kellaways" or "Kelloways Stone" towards the close
of the 18th century. In England it is now usual to speak of the
Kellaways Beds; these comprise (1) the Kellaways Rock, alternating clays
and sands with frequent but irregular concretionary calcareous
sandstones, with abundant fossils; and (2) a lower division, the
Kellaways Clay, which often contains much selenite but is poor in
fossils. The lithological characters are impersistent, and the sandy
phase encroaches sometimes more, sometimes less, upon the true Oxford
Clay. The rocks may be traced from Wiltshire into Bedfordshire,
Lincolnshire and Yorkshire, where they are well exposed in the cliffs at
Scarborough and Gristhorpe, at Hackness (90 ft.), Newtondale (80 ft.)
and Kepwick (100 ft.). In Yorkshire, however, the Callovian rocks lie
upon a somewhat higher palaeontological horizon than in Wiltshire. In
England, _Kepplerites calloviensis_ is taken as the zone fossil; other
common forms are _Cosmoceras modiolare_, _C. gowerianum_, _Belemnites
oweni_, _Ancyloceras calloviense_, _Nautilus calloviensis_, _Avicula
ovalis_, _Gryphaea bilobata_, &c.
On the European continent the "Callovien" stage is used in a sense that
is not exactly synonymous with the English Callovian; it is employed to
embrace beds that lie both higher and lower in the time-scale. Thus, the
continental Callovien includes the following zones:--
Upper Callovien / Zone of _Peltoceras athleta_, _Cosmoceras Duncani_,
(Divesien) \ _Quenstedtoceras Lamberti_ and _Q. mariae._
/ Zone of _Reineckia anceps_, _Stephanoceras
Lower Callovien < coronatum_ and _Cosmoceras jason_ and a lower zone
| of _C. gowerianum_ and _Macrocephalites
\ macrocephalus_.
Rocks of Callovian age (according to the continental classification) are
widely spread in Europe, which, with the exception of numerous insular
masses, was covered by the Callovian Sea. The largest of these land
areas lay over Scandinavia and Finland, and extended eastward as far as
the 40th meridian. In arctic regions these rocks have been discovered in
Spitzbergen, Franz Josef Land, the east coast of Greenland, and Siberia.
They occur in the Hebrides and Skye and in England as indicated above.
In France they are well exposed on the coast of Calvados between
Trouville and Dives, where the marls and clays are 200 ft. thick. In the
Ardennes clays bearing pyrites and oolitic limonite are about 30 ft.
thick. Around Poitiers the Callovian is 100 ft. thick, but the formation
thins in the direction of the Jura.
Clays and shales with ferruginous oolites represent the Callovian of
Germany; while in Russia the deposits of this age are mainly
argillaceous. In North America Callovian fossils are found in
California; in South America in Bolivia. In Africa they have been found
in Algeria and Morocco, in Somaliland and Zanzibar, and on the west
coast of Madagascar. In India they are represented by the shales and
limestones of the Chari series of Cutch. Callovian rocks are also
recorded from New Guinea and the Moluccas.
See JURASSIC; also A. de Lapparent, _Traite de geologie_, vol. ii.
(5th ed., 1906), and H.B. Woodward, "The Jurassic Rocks of Britain,"
_Mem. Geol. Survey_, vol. v. (J. A. H.)
CALM, an adjective meaning peaceful, quiet; particularly used of the
weather, free from wind or storm, or of the sea, opposed to rough. The
word appears in French _calme_, through which it came into English, in
Spanish, Portuguese and Italian _calma_. Most authorities follow Diez
(_Etym. Worterbuch der romanischen Sprachen_) in tracing the origin to
the Low Latin _cauma_, an adaptation of Greek [Greek: kauma], burning
heat, [Greek: kaiein], to burn. The Portuguese _calma_ has this meaning
as well as that of quiet. The connexion would be heat of the day, rest
during that period, so quiet, rest, peacefulness. The insertion of the
_l_, which in English pronunciation disappears, is probably due to the
Latin _calor_, heat, with which the word was associated.
CALMET, ANTOINE AUGUSTIN (1672-1757), French Benedictine, was born at
Mesnil-la-Horgne on the 26th of February 1672. At the age of seventeen
he joined the Benedictine order, and in 1698 was appointed to teach
theology and philosophy at the abbey of Moyen-Moutier. He was
successively prior at Lay, abbot at Nancy and of Senones in Lorraine. He
died in Paris on the 25th of October 1757. The erudition of Calmet's
exegetical writings won him a reputation that was not confined to the
Roman Catholic Church, but they have failed to stand the test of modern
scholarship. The most noteworthy are:--_Commentaire de la Bible_ (Paris,
23 vols. 1707-1716), and _Dictionnaire historique, geographique,
critique, chronologique et litteral de la Bible_ (Paris, 2 vols., 1720).
These and numerous other works and editions of the Bible are known only
to students, but as a pioneer in a branch of Biblical study which
received a wide development in the 19th century, Calmet is worthy of
remembrance. As a historical writer he is best known by his _Histoire
ecclesiastique et civile de la Lorraine_ (Nancy, 1728), founded on
original research and various useful works on Lorraine, of which a full
list is given In Vigouroux's _Dictionnaire de la Bible_.
See A. Digot, _Notice biographique et litteraire sur Dom Augustin
Calmet_ (Nancy, 1860).
CALNE, a market town and municipal borough in the Chippenham
parliamentary division of Wiltshire, England, 99 m. west of London by
the Great Western railway. Pop. (1901) 3457. Area, 356 acres. It lies in
the valley of the Calne, and is surrounded by the high table-land of
Salisbury Plain and the Marlborough Downs. The church of St Mark has a
nave with double aisles, and massive late Norman pillars and arches. The
tower, which fell in 1628, was perhaps rebuilt by Inigo Jones. Other
noteworthy buildings are a grammar school, founded by John Bentley in
1660, and the town-hall. Bacon-curing is the staple industry, and there
are flour, flax and paper mills. The manufacture of broadcloth, once of
great importance, is almost extinct. Calne is governed by a mayor, four
aldermen and twelve councillors.
In the 10th century Calne (_Canna_, _Kalne_) was the site of a palace of
the West-Saxon kings. Calne was the scene of the synod of 978 when,
during the discussion of the question of celibacy, the floor suddenly
gave way beneath the councillors, leaving Archbishop Dunstan alone
standing upon a beam. Here also a witenagemot was summoned in 997. In
the Domesday Survey Calne appears as a royal borough; it comprised
forty-seven burgesses and was not assessed in hides. In 1565 the borough
possessed a gild merchant, at the head of which were two gild stewards.
Calne claimed to have received a charter from Stephen and a confirmation
of the same from Henry III., but no record of these is extant, and the
charter actually issued to the borough by James II. in 1687 apparently
never came into force. The borough returned two members to parliament
more or less irregularly from the first parliament of Edward I. until
the Reform Bill of 1832. From this date the borough returned one member
only until, by the Redistribution of Seats Act of 1885, the privilege
was annulled. In 1303 Lodovicus de Bello Monte, prebendary of
Salisbury, obtained a grant of a Saturday market at the manor of Calne,
and a three days' fair at the feast of St Mary Magdalene; the latter was
only abandoned in the 19th century. Calne was formerly one of the chief
centres of cloth manufacture in the west of England, but the industry is
extinct.
CALOMEL, a drug consisting of mercurous chloride, mercury subchloride,
Hg2Cl2, which occurs in nature as the mineral horn-quicksilver, found as
translucent crystals belonging to the tetragonal system, with an
adamantine lustre, and a dirty white grey or brownish colour. The chief
localities are Idria, Obermoschel, Horowitz in Bavaria and Almaden in
Spain. It was used in medicine as early as the 16th century under the
names _Draco mitigatus, Manna metallorum, Aquila alba, Mercurius
dulcis_; later it became known as calomel, a name probably derived from
the Greek [Greek: kalos], beautiful, and [Greek: melas], black, in
allusion to its blackening by ammonia, or from [Greek: kalos] and
[Greek: meli], honey, from its sweet taste. It may be obtained by
heating mercury in chlorine, or by reducing mercuric chloride (corrosive
sublimate) with mercury or sulphurous acid. It is manufactured by
heating a mixture of mercurous sulphate and common salt in iron retorts,
and condensing the sublimed calomel in brick chambers. In the wet way it
is obtained by precipitating a mercurous salt with hydrochloric acid.
Calomel is a white powder which sublimes at a low red heat; it is
insoluble in water, alcohol and ether. Boiling with stannous chloride
solution reduces it to the metal; digestion with potassium iodide gives
mercurous iodide. Nitric acid oxidizes it to mercuric nitrate, while
potash or soda decomposes it into mercury and oxygen. Long continued
boiling with water gives mercury and mercuric chloride; dilute
hydrochloric acid or solutions of alkaline chlorides convert it into
mercuric chloride on long boiling.
The molecular weight of mercurous chloride has given occasion for much
discussion. E. Mitscherlich determined the vapour density to be 8.3 (air
= 1), corresponding to HgCl. The supporters of the formula Hg2Cl2
pointed out that dissociation into mercury and mercuric chloride would
give this value, since mercury is a monatomic element. After
contradictory evidence as to whether dissociation did or did not occur,
it was finally shown by Victor Meyer and W. Harris (1894) that a rod
moistened with potash and inserted in the vapour was coloured yellow,
and so conclusively proved dissociation. A. Werner determined the
molecular weights of mercurous, cuprous and silver bromides, iodides and
chlorides in pyridine solution, and obtained results pointing to the
formula HgCl, etc. However, the double formula, Hg2Cl2, has been
completely established by H.B. Baker (_Journ. Chem. Soc._, 1900, 77, p.
646) by vapour density determinations of the absolutely dry substance.
Calomel possesses certain special properties and uses in medicine which
are dealt with here as a supplement to the general discussion of the
pharmacology and therapeutics of mercury (q.v.). Calomel exerts remote
actions in the form of mercuric chloride. The specific value of
mercurous chloride is that it exerts the valuable properties of mercuric
chloride in the safest and least irritant manner, as the active salt is
continuously and freshly generated in small quantities. Its
pharmacopeial preparations are the "Black wash," in which calomel and
lime react to form mercurous oxide, a pill still known as "Plummer's
pill" and an ointment. Externally the salt has not any particular
advantage over other mercurial compounds, despite the existence of the
official ointment. Internally the salt is given in doses--for an adult
of from one-half to five grains. It is an admirable aperient, acting
especially on the upper part of the intestinal canal, and causing a
slight increase of intestinal secretion. The stimulant action occurring
high up in the canal (duodenum and jejunum), it is well to follow a dose
of calomel with a saline purgative a few hours afterwards. The special
value of the drug as an aperient depends on its antiseptic power and its
stimulation of the liver. The stools are dark green, containing calomel,
mercuric sulphide and bile which, owing to the antiseptic action, has
not been decomposed. The salt is often used in the treatment of
syphilis, but is probably less useful than certain other mercurial
compounds. It is also employed for fumigation; the patient sits naked
with a blanket over him, on a cane-bottomed chair, under which twenty
grains of calomel are volatilized by a spirit-lamp; in about twenty
minutes the calomel is effectually absorbed by the skin.
CALONNE, CHARLES ALEXANDRE DE (1734-1803), French statesman, was born at
Douai of a good family. He entered the profession of the law, and became
in succession advocate to the general council of Artois, _procureur_ to
the parlement of Douai, master of requests, then intendant of Metz
(1768) and of Lille (1774). He seems to have been a man of great
business capacity, gay and careless in temperament, and thoroughly
unscrupulous in political action. In the terrible crisis of affairs
preceding the French Revolution, when minister after minister tried in
vain to replenish the exhausted royal treasury and was dismissed for
want of success, Calonne was summoned to take the general control of
affairs. He assumed office on the 3rd of November 1783. He owed the
position to Vergennes, who for three years and a half continued to
support him; but the king was not well disposed towards him, and,
according to the testimony of the Austrian ambassador, his reputation
with the public was extremely poor. In taking office he found "600
millions to pay and neither money nor credit." At first he attempted to
develop the latter, and to carry on the government by means of loans in
such a way as to maintain public confidence in its solvency. In October
1785 he recoined the gold coinage, and he developed the _caisse d'
escompte_. But these measures failing, he proposed to the king the
suppression of internal customs, duties and the taxation of the property
of nobles and clergy. Turgot and Necker had attempted these reforms, and
Calonne attributed their failure to the malevolent criticism of the
parlements. Therefore he had an assembly of "notables" called together
in January 1787. Before it he exposed the deficit in the treasury, and
proposed the establishment of a _subvention territoriale_, which should
be levied on all property without distinction. This suppression of
privileges was badly received by the privileged notables. Calonne,
angered, printed his reports and so alienated the court. Louis XVI.
dismissed him on the 8th of April 1787 and exiled him to Lorraine. The
joy was general in Paris, where Calonne, accused of wishing to augment
the imposts, was known as "Monsieur Deficit." In reality his audacious
plan of reforms, which Necker took up later, might have saved the
monarchy had it been firmly seconded by the king. Calonne soon
afterwards passed over to England, and during his residence there kept
up a polemical correspondence with Necker on the finances. In 1789, when
the states-general were about to assemble, he crossed over to Flanders
in the hope of being allowed to offer himself for election, but he was
sternly forbidden to enter France. In revenge he joined the _emigre_
party at Coblenz, wrote in their favour, and expended nearly all the
fortune brought him by his wife, a wealthy widow. In 1802, having again
taken up his abode in London, he received permission from Napoleon to
return to France. He died on the 30th of October 1802, about a month
after his arrival in his native country.
See Ch. Gomel, _Les Causes financieres de la Revolution_ (Paris,
1893); R. Stourm, _Les Finances de l'ancien regime et de la
Revolution_ (2 vols., Paris, 1885); Susane, _La Tactique financiere de
Calonne_, with bibliography (Paris, 1902).
CALORESCENCE (from the Lat. _calor_, heat), a term invented by John
Tyndall to describe an optical phenomenon, the essential feature of
which is the conversion of rays belonging to the dark infra-red portion
of the spectrum into the more refrangible visible rays, i.e. heat rays
into rays of light. Such a transformation had not previously been
observed, although the converse phenomenon, i.e. the conversion of short
waves of light into longer or less refrangible waves, had been shown by
Sir G.G. Stokes to occur in fluorescent bodies. Tyndall's experiments,
however, were carried out on quite different lines, and have nothing to
do with fluorescence (q.v.). His method was to sift out the long dark
waves which are associated with the short visible waves constituting the
light of the sun or of the electric arc and to concentrate the former to
a focus. If the eye was placed at the focus, no sensation of light was
observed, although small pieces of charcoal or blackened platinum foil
were immediately raised to incandescence, thus giving rise to visible
rays.
The experiment is more easily carried out with the electric light than
with sunlight, as the former contains a smaller proportion of visible
rays. According to Tyndall, 90% of the radiation from the electric arc
is non-luminous. The arc being struck in the usual way between two
carbons, a concave mirror, placed close behind it, caused a large part
of the radiation to be directed through an aperture in the camera and
concentrated to a focus outside. In front of the aperture were placed a
plate of transparent rock-salt, and a flat cell of thin glass containing
a solution of iodine in carbon bisulphide. Both rock-salt and carbon
bisulphide are extremely transparent to the luminous and also to the
infra-red rays The iodine in the solution, however, has the property of
absorbing the luminous rays, while transmitting the infra-red rays
copiously, so that in sufficient thicknesses the solution appears nearly
black. Owing to the inflammable nature of carbon bisulphide, the plate
of rock-salt was found to be hardly a sufficient protection, and Tyndall
surrounded the iodine cell with an annular vessel through which cold
water was made to flow. Any small body which was a good absorber of dark
rays was rapidly heated to redness when placed at the focus. Platinized
platinum (platinum foil upon which a thin film of platinum had been
deposited electrolytically) and charcoal were rendered incandescent,
black paper and matches immediately inflamed, ordinary brown paper
pierced and burned, while thin white blotting-paper, owing to its
transparency to the invisible rays, was scarcely tinged. A simpler
arrangement, also employed by Tyndall, is to cause the rays to be
reflected outwards parallel to one another, and to concentrate them by
means of a small flask, containing the iodine solution and used as a
lens, placed some distance from the camera. The rock-salt and cold water
circulation can then be dispensed with.
Since the rays used by Tyndall in these experiments are similar to those
emitted by a heated body which is not hot enough to be luminous, it
might be thought that the radiation, say from a hot kettle, could be
concentrated to a focus and employed to render a small body luminous. It
would, however, be impossible by such means to raise the receiving body
to a higher temperature than the source of radiation. For it is easy to
see that if, by means of lenses of rock-salt or mirrors, we focused all
or nearly all the rays from a small surface on to another surface of
equal area, this would not raise the temperature of the second surface
above that of the first; and we could not obtain a greater concentration
of rays from a large heated surface, since we could not have all parts
of the surface simultaneously in focus. The desired result could be
obtained if it were possible, by reflection or otherwise, to cause two
different rays to unite without loss and pursue a common path. Such a
result must be regarded as impossible of attainment, as it would imply
the possibility of heat passing from one body to another at a higher
temperature, contrary to the second law of thermodynamics (q.v.).
Tyndall used the dark rays from a luminous source, which are emitted in
a highly concentrated form, so that it was possible to obtain a high
temperature, which was, however, much lower than that of the source.
A full account of Tyndall's experiments will be found in his _Heat, a
Mode of Motion_. (J. R. C.)
CALORIMETRY, the scientific name for the measurement of quantities of
heat (Lat. _calor_), to be distinguished from thermometry, which
signifies the measurement of temperature. A calorimeter is any piece of
apparatus in which heat is measured. This distinction of meaning is
purely a matter of convention, but it is very rigidly observed.
Quantities of heat may be measured indirectly in a variety of ways in
terms of the different effects of heat on material substances. The most
important of these effects are (_a_) rise of temperature, (_b_) change
of state, (_c_) transformation of energy.
S 1. The rise of temperature of a body, when heat is imparted to it, is
found to be in general nearly proportional to the quantity of heat
added. The _thermal capacity_ of a body is measured by the quantity of
heat required to raise its temperature one degree, and is necessarily
proportional to the mass of the body for bodies of the same substance
under similar conditions. The _specific heat_ of a substance is
sometimes defined as the thermal capacity of unit mass, but more often
as the ratio of the thermal capacity of unit mass of the substance to
that of unit mass of water at some standard temperature. The two
definitions are identical, provided that the thermal capacity of unit
mass of water, at a standard temperature, is taken as the unit of heat.
But the specific heat of water is often stated in terms of other units.
In any case it is necessary to specify the temperature, and sometimes
also the pressure, since the specific heat of a substance generally
depends to some extent on the external conditions. The methods of
measurement, founded on rise of temperature, may be classed as
_thermometric methods_, since they depend on the observation of change
of temperature with a thermometer. The most familiar of these are the
method of mixture and the method of cooling.
S 2. The _Method of Mixture_ consists in imparting the quantity of
heat to be measured to a known mass of water, or some other standard
substance, contained in a vessel or calorimeter of known thermal
capacity, and in observing the rise of temperature produced, from
which data the quantity of heat may be found as explained in all
elementary text-books. This method is the most generally convenient
and most readily applicable of calorimetric methods, but it is not
always the most accurate, for various reasons. Some heat is generally
lost in transferring the heated body to the calorimeter; this loss may
be minimized by performing the transference rapidly, but it cannot be
accurately calculated or eliminated. Some heat is lost when the
calorimeter is raised above the temperature of its enclosure, and
before the final temperature is reached. This can be roughly estimated
by observing the rate of change of temperature before and after the
experiment, and assuming that the loss of heat is directly
proportional to the duration of the experiment and to the average
excess of temperature. It can be minimized by making the mixing as
rapid as possible, and by using a large calorimeter, so that the
excess of temperature is always small. The latter method was generally
adopted by J.P. Joule, but the rise of temperature is then difficult
to measure with accuracy, since it is necessarily reduced in nearly
the same proportion as the correction. There is, however, the
advantage that the correction is rendered much less uncertain by this
procedure, since the assumption that the loss of heat is proportional
to the temperature-excess is only true for small differences of
temperature. Rumford proposed to eliminate this correction by starting
with the initial temperature of the calorimeter as much below that of
its enclosure as the final temperature was expected to be above the
same limit. This method has been very generally recommended, but it is
really bad, because, although it diminishes the absolute magnitude of
the correction, it greatly increases the uncertainty of it and
therefore the probable error of the result. The coefficient of heating
of a calorimeter when it is below the temperature of its surroundings
is seldom, if ever, the same as the coefficient of cooling at the
higher temperature, since the convection currents, which do most of
the heating or cooling, are rarely symmetrical in the two cases, and
moreover, the duration of the two stages is seldom the same. In any
case, it is desirable to diminish the loss of heat as much as possible
by polishing the exterior of the calorimeter to diminish radiation,
and by suspending it by non-conducting supports, inside a polished
case, to protect it from draughts. It is also very important to keep
the surrounding conditions as constant as possible throughout the
experiment. This may be secured by using a large water-bath to
surround the apparatus, but in experiments of long duration it is
necessary to use an accurate temperature regulator. The method of
lagging the calorimeter with cotton-wool or other non-conductors,
which is often recommended, diminishes the loss of heat considerably,
but renders it very uncertain and variable, and should never be used
in work of precision. The bad conductors take so long to reach a
steady state that the rate of loss of heat at any moment depends on
the past history more than on the temperature of the calorimeter at
the moment. A more serious objection to the use of lagging of this
kind is the danger of its absorbing moisture. The least trace of damp
in the lagging, or of moisture condensed on the surface of the
calorimeter, may produce serious loss of heat by evaporation. This is
another objection to Rumford's method of cooling the calorimeter below
the surrounding temperature before starting. Among minor difficulties
of the method may be mentioned the uncertainty of the thermal capacity
of the calorimeter and stirrer, and of the immersed portion of the
thermometer. This is generally calculated by assuming values for the
specific heats of the materials obtained by experiment between 100
deg. C. and 20 deg. C. Since the specific heats of most metals
increase rapidly with rise of temperature, the values so obtained are
generally too high. It is best to make this correction as small as
possible by using a large calorimeter, so that the mass of water is
large in proportion to that of metal. Analogous difficulties arise in
the application of other calorimetric methods. The accuracy of the
work in each case depends principally on the skill and ingenuity of
the experimentalist in devising methods of eliminating the various
sources of error. The form of apparatus usually adopted for the
method of mixtures is that of Regnault with slight modifications, and
figures and descriptions are given in all the text-books. Among
special methods which have been subsequently developed there are two
which deserve mention as differing in principle from the common type.
These are (1) the constant temperature method, (2) the continuous flow
method.
[Illustration: FIG. 1.]
The _constant temperature method of mixtures_ was proposed by N.
Hesehus (_Jour. Phys._, 1888, vii. p. 489). Cold water at a known
temperature is added to the calorimeter, immediately after dropping in
the heated substance, at such a rate as to keep the temperature of the
calorimeter constant, thus eliminating the corrections for the water
equivalent of the calorimeter and the external loss of heat. The
calorimeter is surrounded by an air-jacket connected to a petroleum
gauge which indicates any small change of temperature in the
calorimeter, and enables the manipulator to adjust the supply of cold
water to compensate it. The apparatus as arranged by F.A. Waterman is
shown in fig. 1 (_Physical Review_, 1896, iv. p. 161). A is the
calorimetric tube, B the air-jacket and L the gauge. H is an electric
heater for raising the body to a suitable temperature, which can swing
into place directly over the calorimeter. W is a conical can
containing water cooled by ice I nearly to 0 deg., which is swung over
the calorimeter as soon as the hot body has been introduced and the
heater removed. The cold water flow is regulated by a tap S with a
long handle O, and its temperature is taken by a delicate thermometer
with its bulb at G. The method is interesting, but the manipulations
and observations involved are more troublesome than with the ordinary
type of calorimeter, and it may be doubted whether any advantage is
gained in accuracy.
[Illustration: Fig. 2.]
The _continuous flow method_ is specially applicable to the important
case of calorific value of gaseous fuel, where a large quantity of
heat is continuously generated at a nearly uniform rate by combustion.
Fig. 2 illustrates a recent type of gas calorimeter devised by C.V.
Boys (_Proc. R.S._, 1906, A. 77, p. 122). The heated products of
combustion from the burner B impinge on a metal box H, through which
water is circulating, and then pass downwards and outwards through a
spiral cooler which reduces them practically to the atmospheric
temperature. A steady stream of water enters the apparatus by the
inflow thermometer O, flows through the spiral coolers N and M, and
finally through the box H, where it is well mixed before passing the
outflow thermometer P. As soon as a steady state is reached, the
difference of temperature between the outflow and inflow thermometers,
multiplied by the current of water in grammes per minute gives the
heat per minute supplied by combustion. The gas current is
simultaneously observed by a suitable meter, which, with subsidiary
corrections for pressure, temperature, &c., gives the necessary data
for deducing calorific value.
A continuous flow calorimeter has been used by the writer for
measuring quantities of heat conveyed by conduction (see CONDUCTION OF
HEAT), and also for determining the variation of the specific heat of
water. In the latter case two steady currents of water at different
temperatures, say 0 deg. and 100 deg. are passed through an equalizer,
and the resulting temperature measured without mixing the currents,
which are then separately determined by weighing. This is a very good
method of comparing the mean specific heats over two ranges of
temperature such as 0-50, and 50-100, or 0-20 and 20-40, but it is not
so suitable as the electric method described below for obtaining the
actual specific heat at any point of the range.
S 3. _Method of Cooling._--A common example of this method is the
determination of the specific heat of a liquid by filling a small
calorimeter with the liquid, raising it to a convenient temperature, and
then setting it to cool in an enclosure at a steady temperature, and
observing the time taken to fall through a given range when the
conditions have become fairly steady. The same calorimeter is afterwards
filled with a known liquid, such as water, and the time of cooling is
observed through the same range of temperature, in the same enclosure,
under the same conditions. The ratio of the times of cooling is equal to
the ratio of the thermal capacities of the calorimeter and its contents
in the two cases. The advantage of the method is that there is no
transference or mixture; the defect is that the whole measurement
depends on the assumption that the rate of loss of heat is the same in
the two cases, and that any variation in the conditions, or uncertainty
in the rate of loss, produces its full effect in the result, whereas in
the previous case it would only affect a small correction. Other sources
of uncertainty are, that the rate of loss of heat generally depends to
some extent on the rate of fall of temperature, and that it is difficult
to take accurate observations on a rapidly falling thermometer. As the
method is usually practised, the calorimeter is made very small, and the
surface is highly polished to diminish radiation. It is better to use a
fairly large calorimeter to diminish the rate of cooling and the
uncertainty of the correction for the water equivalent. The surface of
the calorimeter and the enclosure should be permanently blackened so as
to increase the loss of heat by radiation as much as possible, as
compared with the losses by convection and conduction, which are less
regular. For accurate work it is essential that the liquid in the
calorimeter should be continuously stirred, and also in the enclosure,
the lid of which must be water-jacketed, and kept at the same steady
temperature as the sides. When all these precautions are taken, the
method loses most of the simplicity which is its chief advantage. It
cannot be satisfactorily applied to the case of solids or powders, and
is much less generally useful than the method of mixture.
S 4. _Method of Fusion._--The methods depending on change of state are
theoretically the simplest, since they do not necessarily involve any
reference to thermometry, and the corrections for external loss of heat
and for the thermal capacity of the containing vessels can be completely
eliminated. They nevertheless present peculiar difficulties and
limitations, which render their practical application more troublesome
and more uncertain than is usually supposed. They depend on the
experimental fact that the quantity of heat required to produce a given
change of state (e.g. to convert one gramme of ice at 0 deg. C. into
water at 0 deg. C., or one gramme of water at 100 deg. C. into steam at
100 deg. C.) is always the same, and that there need be no change of
temperature during the process. The difficulties arise in connexion with
the determination of the quantities of ice melted or steam condensed,
and in measuring the latent heat of fusion or vaporization in terms of
other units for the comparison of observations. The earlier forms of
ice-calorimeter, those of Black, and of Laplace and Lavoisier, were
useless for work of precision, on account of the impossibility of
accurately estimating the quantity of water left adhering to the ice in
each case. This difficulty was overcome by the invention of the Bunsen
calorimeter, in which the quantity of ice melted is measured by
observing the diminution of volume, but the successful employment of
this instrument requires considerable skill in manipulation. The sheath
of ice surrounding the bulb must be sufficiently continuous to prevent
escape of heat, but it must not be so solid as to produce risk of
strain. The ideal condition is difficult to secure. In the practical use
of the instrument it is not necessary to know both the latent heat of
fusion of ice and the change of volume which occurs on melting; it is
sufficient to determine the change of volume per calorie, or the
quantity of mercury which is drawn into the bulb of the apparatus per
unit of heat added. This can be determined by a direct calibration, by
inserting a known quantity of water at a known temperature and observing
the contraction, or weighing the mercury drawn into the apparatus. In
order to be independent of the accuracy of the thermometer employed for
observing the initial temperature of the water introduced, it has been
usual to employ water at 100 deg. C., adopting as unit of heat the "mean
calorie," which is one-hundredth part of the heat given up by one gramme
of water in cooling from 100 deg. to 0 deg. C. The weight of mercury
corresponding to the mean calorie has been determined with considerable
care by a number of observers well skilled in the use of the instrument.
The following are some of their results:--Bunsen, 15.41 mgm.; Velten,
15.47 mgm.; Zakrevski, 15.57 mgm.; Staub, 15.26 mgm. The explanation of
these discrepancies in the fundamental constant is not at all clear, but
they may be taken as an illustration of the difficulties of manipulation
attending the use of this instrument, to which reference has already
been made. It is not possible to deduce a more satisfactory value from
the latent heat and the change of density, because these constants are
very difficult to determine. The following are some of the values
deduced by well-known experimentalists for the latent heat of
fusion:--Regnault, 79.06 to 79.24 calories, corrected by Person to
79.43; Person, 79.99 calories; Hess, 80.34 calories; Bunsen, 80.025
calories. Regnault, Person and Hess employed the method of mixture which
is probably the most accurate for the purpose. Person and Hess avoided
the error of water sticking to the ice by using dry ice at various
temperatures below 0 deg. C., and determining the specific heat of ice
as well as the latent heat of fusion. These discrepancies might, no
doubt, be partly explained by differences in the units employed, which
are somewhat uncertain, as the specific heat of water changes rapidly in
the neighbourhood of 0 deg. C; but making all due allowance for this, it
remains evident that the method of ice-calorimetry, in spite of its
theoretical simplicity, presents grave difficulties in its practical
application.
One of the chief difficulties in the practical use of the Bunsen
calorimeter is the continued and often irregular movement of the
mercury column due to slight differences of temperature, or pressure
between the ice in the calorimeter and the ice bath in which it is
immersed. C.V. Boys (_Phil. Mag._, 1887, vol. 24, p. 214) showed that
these effects could be very greatly reduced by surrounding the
calorimeter with an outer tube, so that the ice inside was separated
from the ice outside by an air space which greatly reduces the free
passage of heat. The present writer has found that very good results
may be obtained by enclosing the calorimeter in a vacuum jacket (as
illustrated in fig. 3), which practically eliminates conduction and
convection. If the vacuum jacket is silvered inside, radiation also is
reduced to such an extent that, if the vacuum is really good, the
external ice bath may be dispensed with for the majority of purposes.
If the inner bulb is filled with mercury instead of water and ice, the
same arrangement answers admirably as a Favre and Silbermann
calorimeter, for measuring small quantities of heat by the expansion
of the mercury.
[Illustration: Fig. 3.]
The question has been raised by E.L. Nichols (_Phys. Rev._ vol. 8,
January 1899) whether there may not be different modifications of ice
with different densities, and different values of the latent heat of
fusion. He found for natural pond-ice a density 0.9179 and for
artificial ice 0.9161. J. Vincent (_Phil. Trans._ A. 198, p. 463) also
found a density .9160 for artificial ice, which is probably very
nearly correct. If such variations of density exist, they may
introduce some uncertainty in the absolute values of results obtained
with the ice calorimeter, and may account for some of the
discrepancies above enumerated.
S 5. The _Method of Condensation_ was first successfully applied by J.
Joly in the construction of his steam calorimeter, a full description of
which will be found in text-books. The body to be tested is placed in a
special scale-pan, suspended by a fine wire from the arm of a balance
inside an enclosure which can be filled with steam at atmospheric
pressure. The temperature of the enclosure is carefully observed before
admitting steam. The weight of steam condensed on the body gives a means
of calculating the quantity of heat required to raise it from the
atmospheric temperature up to 100 deg. C. in terms of the latent heat of
vaporization of steam at 100 deg. C. There can be no appreciable gain or
loss of heat by radiation, if the admission of the steam is sufficiently
rapid, since the walls of the enclosure are maintained at 100 deg. C.,
very nearly. The thermal capacity of the scale-pan, &c., can be
determined by a separate experiment, or, still better, eliminated by the
differential method of counterpoising with an exactly similar
arrangement on the other arm of the balance. The method requires very
delicate weighing, as one calorie corresponds to less than two
milligrammes of steam condensed; but the successful application of the
method to the very difficult problem of measuring the specific heat of a
gas at constant volume, shows that these and other difficulties have
been very skilfully overcome. The application of the method appears to
be practically limited to the measurements of specific heat between the
atmospheric temperature and 100 deg. C. The results depend on the value
assumed for the latent heat of steam, which Joly takes as 536.7
calories, following Regnault. Joly has himself determined the mean
specific heat of water between 12 deg. and 100 deg. C. by this method,
in terms of the latent heat of steam as above given, and finds the
result .9952. Assuming that the mean specific heat of water between 12
deg. and 100 deg. is really 1.0011 in terms of the calorie at 20 deg. C.
(see table, p. 66), the value of the latent heat of steam at 100 deg.
C., as determined by Joly, would be 540.2 in terms of the same unit. The
calorie employed by Regnault is to some extent uncertain, but the
difference is hardly beyond the probable errors of experiment, since it
appears from the results of recent experiments that Regnault made an
error of the same order in his determination of the specific heat of
water at 100 deg. C.
S 6. _Energy Methods._--The third general method of calorimetry, that
based on the transformation of some other kind of energy into the form
of heat, rests on the general principle of the conservation of energy,
and on the experimental fact that all other forms of energy are readily
and completely convertible into the form of heat. It is therefore often
possible to measure quantities of heat indirectly, by measuring the
energy in some other form and then converting it into heat. In addition
to its great theoretical interest, this method possesses the advantage
of being frequently the most accurate in practical application, since
energy can be more accurately measured in other forms than in that of
heat. The two most important varieties of the method are (_a_)
mechanical, and (_b_) electrical. These methods have reached their
highest development in connexion with the determination of the
mechanical equivalent of heat, but they may be applied with great
advantage in connexion with other problems, such as the measurement of
the variation of specific heat, or of latent heats of fusion or
vaporization.
S 7. _Mechanical Equivalent of Heat._--The phrase "mechanical equivalent
of heat" is somewhat vague, but has been sanctioned by long usage. It is
generally employed to denote the number of units of mechanical work or
energy which, when completely converted into heat without loss, would be
required to produce one heat unit. The numerical value of the mechanical
equivalent necessarily depends on the particular units of heat and work
employed in the comparison. The British engineer prefers to state
results in terms of foot-pounds of work in any convenient latitude per
pound-degree-Fahrenheit of heat. The continental engineer prefers
kilogrammetres per kilogramme-degree-centigrade. For scientific use the
C.G.S. system of expression in ergs per gramme-degree-centigrade, or
"calorie," is the most appropriate, as being independent of the value of
gravity. A more convenient unit of work or energy, in practice, on
account of the smallness of the erg, is the _joule_, which is equal to
10.7 ergs, or one _watt-second_ of electrical energy. On account of its
practical convenience, and its close relation to the international
electrical units, the _joule_ has been recommended by the British
Association for adoption as the absolute unit of heat. Other convenient
practical units of the same kind would be the _watt-hour_, 3600 joules,
which is of the same order of magnitude as the kilo-calorie, and the
_kilowatt-hour_, which is the ordinary commercial unit of electrical
energy.
S 8. _Joule_.--The earlier work of Joule is now chiefly of historical
interest, but his later measurements in 1878, which were undertaken on
a larger scale, adopting G.A. Hirn's method of measuring the work
expended in terms of the torque and the number of revolutions, still
possess value as experimental evidence. In these experiments (see fig.
4) the paddles were revolved by hand at such a speed as to produce a
constant torque on the calorimeter _h_, which was supported on a float
_w_ in a vessel of water _v_, but was kept at rest by the couple due
to a pair of equal weights _k_ suspended from fine strings passing
round the circumference of a horizontal wheel attached to the
calorimeter. Each experiment lasted about forty minutes, and the rise
of temperature produced was nearly 3 deg. C. The calorimeter contained
about 5 kilogrammes of water, so that the rate of heat-supply was
about 6 calories per second. Joule's final result was 772.55
foot-pounds at Manchester per pound-degree-Fahrenheit at a temperature
of 62 deg. F., but individual experiments differed by as much as 1%.
This result in C.G.S. measure is equivalent to 4.177 joules per
calorie at 16.5 deg. C., on the scale of Joule's mercury thermometer.
His thermometers were subsequently corrected to the Paris scale by A.
Schuster in 1895, which had the effect of reducing the above figure to
4.173.
[Illustration: FIG. 4.]
S 9. _Rowland_.--About the same time H.A. Rowland (_Proc. Amer. Acad._
xv. p. 75, 1880) repeated the experiment, employing the same method,
but using a larger calorimeter (about 8400 grammes) and a petroleum
motor, so as to obtain a greater rate of heating (about 84 calories
per second), and to reduce the importance of the uncertain correction
for external loss of heat. Rowland's apparatus is shown in fig. 5. The
calorimeter was suspended by a steel wire, the torsion of which made
the equilibrium stable. The torque was measured by weights O and P
suspended by silk ribbons passing over the pulleys n and round the
disk kl. The power was transmitted to the paddles by bevel wheels, f,
g, rotating a spindle passing through a stuffing box in the bottom of
the calorimeter. The number of revolutions and the rise of temperature
were recorded on a chronograph drum. He paid greater attention to the
important question of thermometry, and extended his researches over a
much wider range of temperature, namely 5 deg. to 35 deg. C. His
experiments revealed for the first time a diminution in the specific
heat of water with rise of temperature between 0 deg. and 30 deg. C.,
amounting to four parts in 10.000 per 1 deg. C. His thermometers were
compared with a mercury thermometer standardized in Paris, and with a
platinum thermometer standardized by Griffiths. The result was to
reduce the coefficient of diminution of specific heat at 15 deg. C. by
nearly one half, but the absolute value at 20 deg. C. is practically
unchanged. Thus corrected his values are as follows:--
Temperature 10 deg. 15 deg. 20 deg. 25 deg. 30 deg. 35 deg.
Joules per cal. 4.197 4.188 4.181 4.176 4.175 4.177
These are expressed in terms of the hydrogen scale, but the difference
from the nitrogen scale is so small as to be within the limits of
experimental error in this particular case. Rowland himself considered
his results to be probably correct to one part in 500, and supposed
that the greatest uncertainty lay in the comparison of the scale of
his mercury thermometer with the air thermometer. The subsequent
correction, though not carried out strictly under the conditions of
the experiment, showed that the order of accuracy of his work about
the middle of the range from 15 deg. to 25 deg. was at least 1 in
1000, and probably 1 in 2000. At 30 deg. he considered that, owing to
the increasing magnitude and uncertainty of the radiation correction,
there "might be a small error in the direction of making the
equivalent too great, and that the specific heat might go on
decreasing to even 40 deg. C." The results considered with reference
to the variation of the specific heat of water are shown in the curve
marked Rowland in Fig. 6.
[Illustration: FIG. 5.]
S 10. _Osborne Reynolds and W.H. Moorby (Phil. Trans._, 1897, p. 381)
determined the mechanical equivalent of the mean thermal unit between
0 deg. and 100 deg. C., on a very large scale, with a Froude-Reynolds
hydraulic brake and a steam-engine of 100 h.p. This brake is
practically a Joule calorimeter, ingeniously designed to churn the
water in such a manner as to develop the greatest possible resistance.
The admission of water at 0 deg. C. to the brake was controlled by
hand in such a manner as to keep the outflow nearly at the
boiling-point, the quantity of water in the brake required to produce
a constant torque being regulated automatically, as the speed varied,
by a valve worked by the lifting of the weighted lever attached to the
brake.
[Illustration: FIG. 6.]
The accompanying illustration (fig. 7) shows the brake lagged with
cotton-wool, and the 4-ft. lever to which the weights are suspended.
The power of the brake may be estimated by comparison with the size of
the rope pulley seen behind it on the same shaft. With 300 pounds on a
4-ft. lever at 300 revolutions per minute, the rate of generation of
heat was about 12 kilo-calories per second. In spite of the large
range of temperature, the correction for external loss of heat
amounted to only 5%, with the brake uncovered, and was reduced to less
than 2% by lagging. This is the special advantage of working on so
large a scale with so rapid a generation of heat. But, for the same
reason, the method necessarily presents peculiar difficulties, which
were not overcome without great pains and ingenuity. The principal
troubles arose from damp in the lagging which necessitated the
rejection of several trials, and from dissolved air in the water,
causing loss of heat by the formation of steam. Next to the radiation
loss, the most uncertain correction was that for conduction of heat
along the 4-in. shaft. These losses were as far as possible eliminated
by combining the trials in pairs, with different loads on the brake,
assuming that the heat-loss would be the same in the heavy and light
trials, provided that the external temperature and the gradient in the
shaft, as estimated from the temperature of the bearings, were the
same. The values deduced in this manner for the equivalent agreed as
closely as could be expected considering the impossibility of
regulating the external condition of temperature and moisture with any
certainty in an engine-room. The extreme variation of results in any
one series was only from 776.63 to 779.46 ft.-pounds, or less than
1/2%. This variation may have been due to the state of the lagging,
which Moorby distrusted in spite of the great reduction of the
heat-loss, or it may have been partly due to the difficulty of
regulating the speed of the engine and the water-supply to the brake
in such a manner as to maintain a constant temperature in the outflow,
and avoid variations in the heat capacity of the brake. Since hand
regulation is necessarily discontinuous, the speed and the temperature
were constantly varying, so that it was useless to take readings
nearer than the tenth of a degree. The largest variation recorded in
the two trials of which full details are given, was 4-9 deg. F. in two
minutes in the outflow temperature, and four or five revolutions per
minute on the speed. These variations, so far as they were of a purely
accidental nature, would be approximately eliminated on the mean of a
large number of trials, so that the accuracy of the final result would
be of a higher order than might be inferred from a comparison of
separate pairs of trials. Great pains were taken to discuss and
eliminate all the sources of constant error which could be foreseen.
The results of the light trials with 400 ft.-pounds on the brake
differ slightly from those with 600 ft.-pounds. This might be merely
accidental, or it might indicate some constant difference in the
conditions requiring further investigation. It would have been
desirable, if possible, to have tried the effect of a larger range of
variation in the experimental conditions of load and speed, with a
view to detect the existence of constant errors; but owing to the
limitations imposed by the use of a steam-engine, and the difficulty
of securing steady conditions of running, this proved to be
impossible. There can be no doubt, however, that the final result is
the most accurate direct determination of the value of the mean
calorie between 0 deg. and 100 deg. C. in mechanical units. Expressed
in joules per calorie the result is 4.1832, which agrees very closely
with the value found by Rowland as the mean over the range 15 deg. to
20 deg. C. The value 4.183 is independently confirmed in a remarkable
manner by the results of the electrical method described below, which
give 4.185 joules for the mean calorie, if Rowland's value is assumed
as the starting-point, and taken to be 4.180 joules at 20 deg. C.
[Illustration: FIG. 7.]
S 11. _Electrical Methods._--The value of the international electrical
units has by this time been so accurately determined in absolute measure
that they afford a very good, though indirect, method of determining the
mechanical equivalent of heat. But, quite apart from this, electrical
methods possess the greatest value for calorimetry, on account of the
facility and accuracy of regulating and measuring the quantity of heat
supplied by an electric current. The frictional generation of heat in a
metallic wire conveying a current can be measured in various ways, which
correspond to slightly different methods. By Ohm's law, and by the
definition of difference of electric pressure or potential, we obtain
the following alternative expressions for the quantity of heat H in
joules generated in a time T seconds by a current of C amperes flowing
in a wire of resistance R ohms, the difference of potential between the
ends of the wire being E = CR volts:--