(1736-1818), after receiving a good education, distinguished himself in
the Seven Years' War, and most of all by his victory at Johannisberg. As
governor of Burgundy he did much to improve the industries and means of
communication of that province. At the Revolution he took up arms in
behalf of the king, became commander of the "army of Conde," and fought
in conjunction with the Austrians till the peace of Campo Formio in
1797, being during the last year in the pay of England. He then served
the emperor of Russia in Poland, and after that (1800) returned into the
pay of England, and fought in Bavaria. In 1800 Conde arrived in England,
where he resided for several years. On the restoration of Louis XVIII.
he returned to France. He died in Paris in 1818. He wrote _Essai sur la
vie du grand Conde_ (1798).
LOUIS HENRY JOSEPH, duke of Bourbon (1756-1830), son of the last named,
was the last prince of Conde. Several of the earlier events of his life,
especially his marriage with the princess Louise of Orleans, and the
duel that the comte d'Artois provoked by raising the veil of the
princess at a masked ball, caused much scandal. At the Revolution he
fought with the army of the _emigres_ in Liege. Between the return of
Napoleon from Elba and the battle of Waterloo, he headed with no success
a royalist rising in La Vendee. In 1829 he made a will by which he
appointed as his heir the due d'Aumale, and made some considerable
bequests to his mistress, the baronne de Feucheres (q.v.). On the 27th
of August 1830 he was found hanged on the fastening of his window. A
crime was generally suspected, and the princes de Rohan, who were
relatives of the deceased, disputed the will. Their petition, however,
was dismissed by the courts.
Two cadet branches of the house of Conde played an important part: those
of Soissons and Conti. The first, sprung from Charles of Bourbon (b.
1566), son of Louis I., prince of Conde, became extinct in the
legitimate male line in 1641. The second took its origin from Armand of
Bourbon, born in 1629, son of Henry II., prince of Conde, and survived
up to 1814.
See Muret, _L'Histoire de l'armee de Conde_; Chamballand, _Vie de
Louis Joseph, prince de Conde_; Cretineau-Joly, _Histoire des trois
derniers princes de la maison de Conde_; and _Histoire des princes de
Conde_, by the due d'Aumale (translated by R. B. Borthwick, 1872).
CONDE, LOUIS DE BOURBON, PRINCE OF (1530-1569), fifth son of Charles de
Bourbon, duke of Vendome, younger brother of Antoine, king of Navarre
(1518-1562), was the first of the famous house of Conde (see above).
After his father's death in 1537 Louis was educated in the principles of
the reformed religion. Brave though deformed, gay but extremely poor for
his rank, Conde was led by his ambition to a military career. He fought
with distinction in Piedmont under Marshal de Brissac; in 1552 he forced
his way with reinforcements into Metz, then besieged by Charles V.; he
led several brilliant sorties from that town; and in 1554 commanded the
light cavalry on the Meuse against Charles. In 1557 he was present at
the battle of St Quentin, and did further good service at the head of
the light horse. But the descendants of the constable de Bourbon were
still looked upon with suspicion in the French court, and Conde's
services were ignored. The court designed to reduce his narrow means
still further by despatching him upon a costly mission to Philip II. of
Spain. His personal griefs thus combined with his religious views to
force upon him a role of political opposition. He was concerned in the
conspiracy of Amboise, which aimed at forcing from the king the
recognition of the reformed religion. He was consequently condemned to
death, and was only saved by the decease of Francis II. At the accession
of the boy-king Charles IX., the policy of the court was changed, and
Conde received from Catherine de' Medici the government of Picardy. But
the struggle between the Catholics and the Huguenots soon began once
more, and henceforward the career of Conde is the story of the wars of
religion (see FRANCE: _HISTORY_). He was the military as well as the
political chief of the Huguenot party, and displayed the highest
generalship on many occasions, and notably at the battle of St Denis. At
the battle of Jarnac, with only 400 horsemen, Conde rashly charged the
whole Catholic army. Worn out with fighting, he at last gave up his
sword, and a Catholic officer named Montesquiou treacherously shot him
through the head on the 13th of March 1569.
CONDE, LOUIS II. DE BOURBON, PRINCE OF (1621-1686), called the Great
Conde, was the son of Henry, prince of Conde, and Charlotte Marguerite
de Montmorency, and was born at Paris on the 8th of September 1621. As a
boy, under his father's careful supervision, he studied diligently at
the Jesuits' College at Bourges, and at seventeen, in the absence of his
father, he governed Burgundy. The duc d'Enghien, as he was styled during
his father's lifetime, took part with distinction in the campaigns of
1640 and 1641 in northern France while yet under twenty years of age.
During the youth of Enghien all power in France was in the hands of
Richelieu; to him even the princes of the blood had to yield; and Henry
of Conde sought with the rest to win the cardinal's favour. Enghien was
forced to conform. He was already deeply in love with Mlle. Marthe du
Vigean, who in return was passionately devoted to him, yet, to flatter
the cardinal, he was compelled by his father, at the age of twenty, to
give his hand to Richelieu's niece, Claire Clemence de Maille-Breze, a
child of thirteen. He was present with Richelieu during the dangerous
plot of Cinq Mars, and afterwards fought in the siege of Perpignan
(1642).
In 1643 Enghien was appointed to command against the Spaniards in
northern France. He was opposed by experienced generals, and the
veterans of the Spanish army were accounted the finest soldiers in
Europe; on the other hand, the strength of the French army was placed at
his command, and under him were the best generals of the service. The
great battle of Rocroy (May 18) put an end to the supremacy of the
Spanish army and inaugurated the long period of French military
predominance. Enghien himself conceived and directed the decisive
attack, and at the age of twenty-two won his place amongst the great
captains of modern times. After a campaign of uninterrupted success,
Enghien returned to Paris in triumph, and in gallantry and intrigues
strove to forget his enforced and hateful marriage. In 1644 he was sent
with reinforcements into Germany to the assistance of Turenne, who was
hard pressed, and took command of the whole army. The battle of Freiburg
(Aug.) was desperately contested, but in the end the French army won a
great victory over the Bavarians and Imperialists commanded by Count
Mercy. As after Rocroy, numerous fortresses opened their gates to the
duke. The next winter Enghien spent, like every other winter during the
war, amid the gaieties of Paris. The summer campaign of 1645 opened with
the defeat of Turenne by Mercy, but this was retrieved in the brilliant
victory of Nordlingen, in which Mercy was killed, and Enghien himself
received several serious wounds. The capture of Philipsburg was the most
important of his other achievements during this campaign. In 1646
Enghien served under the duke of Orleans in Flanders, and when, after
the capture of Mardyck, Orleans returned to Paris, Enghien, left in
command, captured Dunkirk (October 11th).
It was in this year that the old prince of Conde died. The enormous
power that fell into the hands of his successor was naturally looked
upon with serious alarm by the regent and her minister. Conde's birth
and military renown placed him at the head of the French nobility; but,
added to that, the family of which he was chief was both enormously rich
and master of no small portion of France. Conde himself held Burgundy,
Berry and the marches of Lorraine, as well as other less important
territory; his brother Conti held Champagne, his brother-in-law,
Longueville, Normandy. The government, therefore, determined to permit
no increase of his already overgrown authority, and Mazarin made an
attempt, which for the moment proved successful, at once to find him
employment and to tarnish his fame as a general. He was sent to lead the
revolted Catalans. Ill-supported, he was unable to achieve anything,
and, being forced to raise the siege of Lerida, he returned home in
bitter indignation. In 1648, however, he received the command in the
important field of the Low Countries; and at Lens (Aug. 19th) a battle
took place, which, beginning with a panic in his own regiment, was
retrieved by Conde's coolness and bravery, and ended in a victory that
fully restored his prestige.
In September of the same year Conde was recalled to court, for the
regent Anne of Austria required his support. Influenced by the fact of
his royal birth and by his arrogant scorn for the bourgeois, Conde lent
himself to the court party, and finally, after much hesitation, he
consented to lead the army which was to reduce Paris (Jan. 1649).
On his side, insufficient as were his forces, the war was carried on
with vigour, and after several minor combats their substantial losses
and a threatening of scarcity of food made the Parisians weary of the
war. The political situation inclined both parties to peace, which was
made at Rueil on the 20th of March (see Fronde, The). It was not long,
however, before Conde became estranged from the court. His pride and
ambition earned for him universal distrust and dislike, and the personal
resentment of Anne in addition to motives of policy caused the sudden
arrest of Conde, Conti and Longueville on the 18th of January 1650. But
others, including Turenne and his brother the duke of Bouillon, made
their escape. Vigorous attempts for the release of the princes began to
be made. The women of the family were now its heroes. The dowager
princess claimed from the parlement of Paris the fulfilment of the
reformed law of arrest, which forbade imprisonment without trial. The
duchess of Longueville entered into negotiations with Spain; and the
young princess of Conde, having gathered an army around her, obtained
entrance into Bordeaux and the support of the parlement of that town.
She alone, among the nobles who took part in the folly of the Fronde,
gains our respect and sympathy. Faithful to a faithless husband, she
came forth from the retirement to which he had condemned her, and
gathered an army to fight for him. But the delivery of the princes was
brought about in the end by the junction of the old Fronde (the party of
the parlement and of Cardinal de Retz) and the new Fronde (the party of
the Condes); and Anne was at last, in February 1651, forced to liberate
them from their prison at Havre. Soon afterwards, however, another
shifting of parties left Conde and the new Fronde isolated. With the
court and the old Fronde in alliance against him, Conde found no
resource but that of making common cause with the Spaniards, who were at
war with France. The confused civil war which followed this step (Sept.
1651) was memorable chiefly for the battle of the Faubourg St Antoine,
in which Conde and Turenne, two of the foremost captains of the age,
measured their strength (July 2, 1652), and the army of the prince was
only saved by being admitted within the gates of Paris. La Grande
Mademoiselle, daughter of the duke of Orleans, persuaded the Parisians
to act thus, and turned the cannon of the Bastille on Turenne's army.
Thus Conde, who as usual had fought with the most desperate bravery, was
saved, and Paris underwent a new investment. This ended in the flight of
Conde to the Spanish army (Sept. 1652), and thenceforward, up to the
peace, he was in open arms against France, and held high command in the
army of Spain. But his now fully developed genius as a commander found
little scope in the cumbrous and antiquated system of war practised by
the Spaniards, and though he gained a few successes, and man[oe]uvred
with the highest possible skill against Turenne, his disastrous defeat
at the Dunes near Dunkirk (14th of June 1658), in which an English
contingent of Cromwell's veterans took part on the side of Turenne, led
Spain to open negotiations for peace. After the peace of the Pyrenees in
1659, Conde obtained his pardon (January 1660) from Louis, who thought
him less dangerous as a subject than as possessor of the independent
sovereignty of Luxemburg, which had been offered him by Spain as a
reward for his services.
Conde now realized that the period of agitation and party warfare was at
an end, and he accepted, and loyally maintained henceforward, the
position of a chief subordinate to a masterful sovereign. Even so, some
years passed before he was recalled to active employment, and these
years he spent on his estate at Chantilly. Here he gathered round him a
brilliant company, which included many men of genius--Moliere, Racine,
Boileau, La Fontaine, Nicole, Bourdaloue and Bossuet. About this time
negotiations between the Poles, Conde and Louis were carried on with a
view to the election, at first of Conde's son Enghien, and afterwards of
Conde himself, to the throne of Poland. These, after a long series of
curious intrigues, were finally closed in 1674 by the veto of Louis XIV.
and the election of John Sobieski. The prince's retirement, which was
only broken by the Polish question and by his personal intercession on
behalf of Fouquet in 1664, ended in 1668. In that year he proposed to
Louvois, the minister of war, a plan for seizing Franche-Comte, the
execution of which was entrusted to him and successfully carried out. He
was now completely re-established in the favour of Louis, and with
Turenne was the principal French commander in the celebrated campaign of
1672 against the Dutch. At the forcing of the Rhine passage at Tollhuis
(June 12) he received a severe wound, after which he commanded in Alsace
against the Imperialists. In 1673 he was again engaged in the Low
Countries, and in 1674 he fought his last great battle at Seneff against
the prince of Orange (afterwards William III. of England). This battle,
fought on the 11th of August, was one of the hardest of the century, and
Conde, who displayed the reckless bravery of his youth, had three horses
killed under him. His last campaign was that of 1675 on the Rhine, where
the army had been deprived of its general by the death of Turenne; and
where by his careful and methodical strategy he repelled the invasion of
the Imperial army of Montecucculi. After this campaign, prematurely worn
out by the toils and excesses of his life, and tortured by the gout, he
returned to Chantilly, where he spent the eleven years that remained to
him in quiet retirement. In the end of his life he specially sought the
companionship of Bourdaloue, Nicole and Bossuet, and devoted himself to
religious exercises. He died on the 11th of November 1686 at the age of
sixty-five. Bourdaloue attended him at his death-bed, and Bossuet
pronounced his _eloge_.
The earlier political career of Conde was typical of the great French
noble of his day. Success in love and war, predominant influence over
his sovereign and universal homage to his own exaggerated pride, were
the objects of his ambition. Even as an exile he asserted the precedence
of the royal house of France over the princes of Spain and Austria, with
whom he was allied for the moment. But the Conde of 1668 was no longer a
politician and a marplot; to be first in war and in gallantry was still
his aim, but for the rest he was a submissive, even a subservient,
minister of the royal will. It is on his military character, however,
that his fame rests. This changed but little. Unlike his great rival
Turenne, Conde was equally brilliant in his first battle and in his
last. The one failure of his generalship was in the Spanish Fronde, and
in this everything united to thwart his genius; only on the battlefield
itself was his personal leadership as conspicuous as ever. That he was
capable of waging a methodical war of positions may be assumed from his
campaigns against Turenne and Montecucculi, the greatest generals of the
predominant school. But it was in his eagerness for battle, his quick
decision in action, and the stern will which sent his regiments to face
the heaviest loss, that Conde is distinguished above all the generals of
his time. In private life he was harsh and unamiable, seeking only the
gratification of his own pleasures and desires. His enforced and
loveless marriage embittered his life, and it was only in his last
years, when he had done with ambition, that the more humane side of his
character appeared in his devotion to literature.
Conde's unhappy wife had some years before been banished to Chateauroux.
An accident brought about her ruin. Her contemporaries, greedy as they
were of scandal, refused to believe any evil of her, but the prince
declared himself convinced of her unfaithfulness, placed her in
confinement, and carried his resentment so far that his last letter to
the king was to request him never to allow her to be released.
AUTHORITIES.--See, besides the numerous _Memoires_ of the time, Puget
de la Serre, _Les Sieges, les batailles, &c., de Mr. le prince de
Conde_ (Paris, 1651); J. de la Brune, _Histoire de la vie, &c., de
Louis de Bourbon, prince de Conde_ (Cologne, 1694); P. Coste,
_Histoire de Louis de Bourbon, &c._ (Hague, 1748); Desormeaux,
_Histoire de Louis de Bourbon, &c._ (Paris, 1768); Turpin, _Vie de
Louis de Bourbon, &c._ (Paris and Amsterdam, 1767); _Eloge militaire
de Louis de Bourbon_ (Dijon, 1772); _Histoire du grand Conde_, by A.
Lemercier (Tours, 1862); J. J. E. Roy (Lille, 1859); L. de Voivreuil
(Tours, 1846); Fitzpatrick, _The Great Conde_, and Lord Mahon, _Life
of Louis, prince of Conde_ (London, 1845). Works on the Conde family
by the prince de Conde and de Sevilinges (Paris, 1820), the due
d'Aumale, and Guibout (Rouen, 1856), should also be consulted.
CONDE, the name of some twenty villages in France and of two towns of
some importance. Of the villages, Conde-en-Brie (Lat. _Condetum_) is a
place of great antiquity and was in the middle ages the seat of a
principality, a sub-fief of that of Montmirail; Conde-sur-Aisne
(_Condatus_) was given in 870 by Charles the Bald to the abbey of St
Ouen at Rouen, gave its name to a seigniory during the middle ages, and
possessed a priory of which the church and a 12th-century chapel remain;
Conde-sur-Marne (_Condate_), once a place of some importance, preserves
one of its parish churches, with a fine Romanesque tower. The two towns
are:--
1. CONDE-SUR-L'ESCAUT, in the department of Nord, at the junction of the
canals of the Scheldt and of Conde-Mons. Pop. (1906) town, 2701;
commune, 5310. It lies 7 m. N. by E. of Valenciennes and 2 m. from the
Belgian frontier. It has a church dating from the middle of the 18th
century. Trade is in coal and cattle. The industries include brewing,
rope-making and boat-building, and there is a communal college. Conde
(_Condate_) is of considerable antiquity, dating at least from the later
Roman period. Taken in 1676 by Louis XIV., it definitely passed into the
possession of France by the treaty of Nijmwegen two years later, and was
afterwards fortified by Vauban. During the revolutionary war it was
besieged and taken by the Austrians (1793); and in 1815 it again fell to
the allies. It was from this place that the princes of Conde (q.v.) took
their title. See Perron-Gelineau, _Conde ancien et moderne_ (Nantes,
1887).
2. CONDE-SUR-NOIREAU, in the department of Calvados, at the confluence
of the Noireau and the Drouance, 33 m. S.S.W. of Caen on the Ouest-Etat
railway. Pop. (1906) 5709. The town is the seat of a tribunal of
commerce, a board of trade-arbitration and a chamber of arts and
manufactures, and has a communal college. It is important for its
cotton-spinning and weaving, and carries on dyeing, printing and
machine-construction; there are numerous nursery-gardens in the
vicinity. Important fairs are held in the town. The church of St Martin
has a choir of the 12th and 15th centuries, and a stained-glass window
(15th century) representing the Crucifixion. There is a statue to Dumont
d'Urville, the navigator (b. 1790), a native of the town. Throughout the
middle ages Conde (_Condatum_, _Condetum_) was the seat of an important
castellany, which was held by a long succession of powerful nobles and
kings, including Robert, count of Mortain, Henry II. and John of
England, Philip Augustus of France, Charles II. (the Bad) and Charles
III. of Navarre. The place was held by the English from 1417 to 1449. Of
the castle some ruins of the keep survive. See L. Huet, _Hist. de
Conde-sur-Noireau, ses seigneurs, son industrie, &c._ (Caen, 1883).
CONDE, JOSE ANTONIO (1766-1820), Spanish Orientalist, was born at
Peraleja (Cuenca) on the 28th of October 1766, and was educated at the
university of Alcala. His translation of Anacreon (1791) obtained him a
post in the royal library in 1795, and in 1796-1797 he published
paraphrases from Theocritus, Bion, Moschus, Sappho and Meleager. These
were followed by a mediocre edition of the Arabic text of Edrisi's
_Description of Spain_ (1799), with notes and a translation. Conde
became a member of the Spanish Academy in 1802 and of the Academy of
History in 1804, but his appointment as interpreter to Joseph Bonaparte
led to his expulsion from both bodies in 1814. He escaped to France in
February 1813, and returned to Spain in 1814, but was not allowed to
reside at Madrid till 1816. Two years later he was re-elected by both
academies; he died in poverty on the 12th of June 1820. His _Historia de
la Dominacion de los Arabes en Espana_ was published in 1820-1821. Only
the first volume was corrected by the author, the other two being
compiled from his manuscript by Juan Tineo. This work was translated
into German (1824-1825), French (1825) and English (1854). Conde's
pretensions to scholarship have been severely criticized by Dozy, and
his history is now discredited. It had, however, the merit of
stimulating abler workers in the same field.
CONDENSATION OF GASES.
Critical temperature.
If the volume of a gas continually decreases at a constant temperature,
for which an increasing pressure is required, two cases may occur:--(1)
The volume may continue to be homogeneously filled. (2) If the substance
is contained in a certain volume, and if the pressure has a certain
value, the substance may divide into two different phases, each of which
is again homogeneous. The value of the temperature T decides which case
will occur. The temperature which is the limit above which the space
will always be homogeneously filled, and below which the substance
divides into two phases, is called the _critical temperature_ of the
substance. It differs greatly for different substances, and if we
represent it by Tc, the condition for the condensation of a gas is that
T must be below Tc. If the substance is divided into two phases, two
different cases may occur. The denser phase may be either a liquid or a
solid. The limiting temperature for these two cases, at which the
division into three phases may occur, is called the _triple point_. Let
us represent it by T3; if the term "condensation of gases" is taken in
the sense of "liquefaction of gases"--which is usually done--the
condition for condensation is Tc > T > T3. The opinion sometimes held
that for all substances T3 is the same fraction of Tc (the value being
about 1/2) has decidedly not been rigorously confirmed. Nor is this to
be expected on account of the very different form of crystallization
which the solid state presents. Thus for carbon dioxide, CO2, for which
Tc = 304 deg. on the absolute scale, and for which we may put T3 = 216
deg., this fraction is about 0.7; for water it descends down to 0.42,
and for other substances it may be still lower.
If we confine ourselves to temperatures between Tc and T3, the gas will
pass into a liquid if the pressure is sufficiently increased. When the
formation of liquid sets in we call the gas a _saturated vapour_. If the
decrease of volume is continued, the gas pressure remains constant till
all the vapour has passed into liquid. The invariability of the
properties of the phases is in close connexion with the invariability of
the pressure (called _maximum tension_). Throughout the course of the
process of condensation these properties remain unchanged, provided the
temperature remain constant; only the relative quantity of the two
phases changes. Until all the gas has passed into liquid a further
decrease of volume will not require increase of pressure. But as soon as
the liquefaction is complete a slight decrease of volume will require a
great increase of pressure, liquids being but slightly compressible.
Critical pressure.
The pressure required to condense a gas varies with the temperature,
becoming higher as the temperature rises. The highest pressure will
therefore be found at Tc and the lowest at T3. We shall represent the
pressure at Tc by pc. It is called the _critical pressure_. The pressure
at T3 we shall represent by p3. It is called the _pressure of the triple
point_. The values of Tc and pc for different substances will be found
at the end of this article. The values of T3 and p3 are accurately known
only for a few substances. As a rule p3 is small, though occasionally it
is greater than 1 atmosphere. This is the case with CO2, and we may in
general expect it if the value of T3/Tc is large. In this case there can
only be a question of a real boiling-point (under the normal pressure)
if the liquid can be supercooled.
We may find the value of the pressure of the saturated vapour for each T
in a geometrical way by drawing in the theoretical isothermal a straight
line parallel to the v-axis in such a way that [int] v1 to v2 pdv will
have the same value whether the straight line or the theoretical
isothermal is followed. This construction, given by James Clerk Maxwell,
may be considered as a result of the application of the general rules
for coexisting equilibrium, which we owe to J. Willard Gibbs. The
construction derived from the rules of Gibbs is as follows:--Construe
the free energy at a constant temperature, i.e. the quantity - [int]pdv
as ordinate, if the abscissa represents v, and determine the inclination
of the double tangent. Another construction derived from the rules of
Gibbs might be expressed as follows:--Construe the value of pv -
[int]pdv as ordinate, the abscissa representing p, and determine the
point of intersection of two of the three branches of this curve.
As an approximate half-empirical formula for the calculation of the
pressure,
p /Tc-T\
-log10 --- = f( ---- )
pc \ T /
may be used. It would follow from the law of corresponding states that
in this formula the value of [int] is the same for all substances, the
molecules of which do not associate to form larger molecule-complexes.
In fact, for a great many substances, we find a value for f, which
differs but little from 3, e.g. ether, carbon dioxide, benzene, benzene
derivatives, ethyl chloride, ethane, &c. As the chemical structure of
these substances differs greatly, and association, if it takes place,
must largely depend upon the structure of the molecule, we conclude from
this approximate equality that the fact of this value of [int] being
equal to about 3 is characteristic for normal substances in which,
consequently, association is excluded. Substances known to associate,
such as organic acids and alcohols, have a sensibly higher value of f.
Thus T. Estreicher (Cracow, 1896) calculates that for fluor-benzene f
varies between 3.07 and 2.94; for ether between 3.0 and 3.1; but for
water between 3.2 and 3.33, and for methyl alcohol between 3.65 and
3.84, &c. For isobutyl alcohol [int] even rises above 4. It is, however,
remarkable that for oxygen [int] has been found almost invariably equal
to 2.47 from K. Olszewski's observations, a value which is appreciably
smaller than 3. This fact makes us again seriously doubt the correctness
of the supposition that [int] = 3 is a characteristic for
non-association.
Critical volume.
It is a general rule that the volume of saturated vapour decreases when
the temperature is raised, while that of the coexisting liquid
increases. We know only one exception to this rule, and that is the
volume of water below 4 deg. C. If we call the liquid volume v_l, and the
vapour v_v, v_v - v_l decreases if the temperature rises, and becomes
zero at Tc. The limiting value, to which vl and vv converge at Tc, is
called the _critical volume_, and we shall represent it by v_c.
According to the law of corresponding states the values both of v_l/v_c
and vv/vc must be the same for all substances, if T/Tc has been taken
equal for them all. According to the investigations of Sydney Young,
this holds good with a high degree of approximation for a long series of
substances. Important deviations from this rule for the values of vv/vl
are only found for those substances in which the existence of
association has already been discovered by other methods. Since the
lowest value of T, for which investigations on v_l and v_v may be made,
is the value of T3; and since T3/Tc, as has been observed above, is not
the same for all substances, we cannot expect the smallest value of
v_l/v_c to be the same for all substances. But for low values of T, viz.
such as are near T3, the influence of the temperature on the volume is
but slight, and therefore we are not far from the truth if we assume the
minimum value of the ratio v_l/v_c as being identical for all normal
substances, and put it at about 1/3. Moreover, the influence of the
polymerization (association) on the liquid volume appears to be small,
so that we may even attribute the value 1/3 to substances which are not
normal. The value of v_v/v_c at T = T3 differs widely for different
substances. If we take p3 so low that the law of Boyle-Gay Lussac may be
applied, we can calculate v3/v_c by means of the formula p3.v3/T3 =
k.p_c.v_c/Tc provided k be known. According to the observations of
Sydney Young, this factor has proved to be 3.77 for normal substances.
In consequence
v3 p_c T3
--- = 3.77 --- --.
v_c p3 Tc
A similar formula, but with another value of k, may be given for
associating substances, provided the saturated vapour does not contain
any complex molecules. But if it does, as is the case with acetic acid,
we must also know the degree of association. It can, however, only be
found by measuring the volume itself.
Rule of the rectilinear diameter.
E. Mathias has remarked that the following relation exists between the
densities of the saturated vapour and of the coexisting liquid:--
/ T \
[rho]l + [rho]v = 2[rho]c {1 + a(1 - -- ) },
\ Tc/
and that, accordingly, the curve which represents the densities at
different temperatures possesses a rectilinear diameter. According to
the law of corresponding states, a would be the same for all substances.
Many substances, indeed, actually appear to have a rectilinear diameter,
and the value of a appears approximatively to be the same. In a _Memoire
presente a la societe royale a Liege_, 15th June 1899, E. Mathias gives
a list of some twenty substances for which a has a value lying between
0.95 and 1.05. It had been already observed by Sydney Young that a is
not perfectly constant even for normal substances. For associating
substances the diameter is not rectilinear. Whether the value of a, near
1, may serve as a characteristic for normal substances is rendered
doubtful by the fact that for nitrogen a is found equal to 0.6813 and
for oxygen to 0.8. At T = Tc/2, the formula of E. Mathias, if [rho]v be
neglected with respect to [rho]l, gives the value 2 + a for
[rho]l/[rho]c.
Latent heat.
The heat required to convert a molecular quantity of liquid coexisting
with vapour into saturated vapour at the same temperature is called
_molecular latent heat_. It decreases with the rise of the temperature,
because at a higher temperature the liquid has already expanded, and
because the vapour into which it has to be converted is denser. At the
critical temperature it is equal to zero on account of the identity of
the liquid and the gaseous states. If we call the molecular weight m and
the latent heat per unit of weight r, then, according to the law of
corresponding states, mr/T is the same for all normal substances,
provided the temperatures are corresponding. According to F. T. Trouton,
the value of mr/T is the same for all substances if we take for T the
boiling-point. As the boiling-points under the pressure of one
atmosphere are generally not equal fractions of Tc, the two theorems are
not identical; but as the values of p_c for many substances do not differ
so much as to make the ratios of the boiling-points under the pressure
of one atmosphere differ greatly from the ratios of Tc, an approximate
confirmation of the law of Trouton may be compatible with an approximate
confirmation of the consequence of the law of corresponding states. If
we take the term boiling-point in a more general sense, and put T in the
law of Trouton to represent the boiling-point under an arbitrary equal
pressure, we may take the pressure equal to pc for a certain substance.
For this substance mr/T would be equal to zero, and the values of mr/T
would no longer show a trace of equality. At present direct trustworthy
investigations about the value of r for different substances are
wanting; hence the question whether as to the quantity mr/T the
substances are to be divided into normal and associating ones cannot be
answered. Let us divide the latent heat into heat necessary for internal
work and heat necessary for external work. Let r' represent the former
of these two quantities, then:--
r = r' + p(v_v - v_l).
Then the same remark holds good for mr'/T as has been made for mr/T. The
ratio between r and that part that is necessary for external work is
given in the formula,
r T dp
------------ = ----.
p(v_v - v_l) p dT
By making use of the approximate formula for the vapour tension:--
p /Tc - T\
log_[epsilon] --- = [int]' (--------), we find--
p_c \ T /
r Tc
------------ = [int]' --.
p(v_v - v_l) T
At T = Tc we find for this ratio [int]', a value which, for normal
substances is equal to 3/0.4343 = 7. At the critical temperature the
quantities r and vv-vl are both equal to 0, but they have a finite
ratio. As we may equate p(v_v - v_l) with pv_v = RT at very low
temperatures, we get, if we take into consideration that R expressed in
calories is nearly equal to 2/m, the value 2[int]'Tc = 14Tc as limiting
value for mr for normal substances. This value for mr has, however,
merely the character of a rough approximation--especially since the
factor f' is not perfectly constant.
Nature of a liquid.
All the phenomena which accompany the condensation of gases into liquids
may be explained by the supposition, that the condition of aggregation
which we call liquid differs only in quantity, and not in quality, from
that which we call gas. We imagine a gas to consist of separate
molecules of a certain mass [mu], having a certain velocity depending on
the temperature. This velocity is distributed according to the law of
probabilities, and furnishes a quantity of _vis viva_ proportional to
the temperatures. We must attribute extension to the molecules, and they
will attract one another with a force which quickly decreases with the
distance. Even those suppositions which reduce molecules to centra of
forces, like that of Maxwell, lead us to the result that the molecules
behave in mutual collisions as if they had extension--an extension which
in this case is not constant, but determined by the law of repulsion in
the collision, the law of the distribution, and the value of the
velocities. In order to explain capillary phenomena it was assumed so
early as Laplace, that between the molecules of the same substance an
attraction exists which quickly decreases with the distance. That this
attraction is found in gases too is proved by the fall which occurs in
the temperature of a gas that is expanded without performing external
work. We are still perfectly in the dark as to the cause of this
attraction, and opinion differs greatly as to its dependence on the
distance. Nor is this knowledge necessary in order to find the influence
of the attraction, for a homogeneous state, on the value of the external
pressure which is required to keep the moving molecules at a certain
volume (T being given). We may, viz., assume either in the strict sense,
or as a first approximation, that the influence of the attraction is
quite equal to a pressure which is proportional to the square of the
density. Though this molecular pressure is small for gases, yet it will
be considerable for the great densities of liquids, and calculation
shows that we may estimate it at more than 1000 atmos., possibly
increasing up to 10,000. We may now make the same supposition for a
liquid as for a gas, and imagine it to consist of molecules, which for
non-associating substances are the same as those of the rarefied vapour;
these, if T is the same, have the same mean _vis viva_ as the vapour
molecules, but are more closely massed together. Starting from this
supposition and all its consequences, van der Waals derived the
following formula which would hold both for the liquid state and for the
gaseous state:--
/ a \
(p + --- )(v - b) = RT.
\ v^2/
It follows from this deduction that for the rarefied gaseous state b
would be four times the volume of the molecules, but that for greater
densities the factor 4 would decrease. If we represent the volume of the
molecules by [beta], the quantity b will be found to have the following
form:--
{ /4[beta]\ /4[beta]\^2 }
b = 4[beta]{ 1 - [gamma]1( ------- ) + [gamma]2( ------- ) &c.}
{ \ v / \ v / }
Only two of the successive coefficients [gamma]1, [gamma]2, &c., have
been worked out, for the determination requires very lengthy
calculations, and has not even led to definitive results (L. Boltzmann,
_Proc. Royal Acad. Amsterdam_, March 1899). The latter formula supposes
the molecules to be rigid spheres of invariable size. If the molecules
are things which are compressible, another formula for b is found, which
is different according to the number of atoms in the molecule (_Proc.
Royal Acad. Amsterdam_, 1900-1901). If we keep the value of a and b
constant, the given equation will not completely represent the net of
isothermals of a substance. Yet even in this form it is sufficient as to
the principal features. From it we may argue to the existence of a
critical temperature, to a minimum value of the product pv, to the law
of corresponding states, &c. Some of the numerical results to which it
leads, however, have not been confirmed by experience. Thus it would
follow from the given equation that p_c.v_c/Tc = 3/8.pv/T, if the value
of v is taken so great that the gaseous laws may be applied, whereas
Sydney Young has found 1/3.77 for a number of substances instead of the
factor 3/8. Again it follows from the given equation, that if a is
thought to be independent of the temperature, Tc/p_c.(dp/dT)_c = 4
whereas for a number of substances a value is found for it which is near
7. If we assume with Clausius that a depends on the temperature, and has
a value a'.273/T, we find Tc/p_c.(dp/dT)_c = 7 That the accurate
knowledge of the equation of state is of the highest importance is
universally acknowledged, because, in connexion with the results of
thermodynamics, it will enable us to explain all phenomena relating to
ponderable matter. This general conviction is shown by the numerous
efforts made to complete or modify the given equation, or to replace it
by another, for instance, by R. Clausius, P. G. Tait, E. H. Amagat, L.
Boltzmann, T. G. Jager, C. Dieterici, B. Galitzine, T. Rose Innes and M.
Reinganum.
If we hold to the supposition that the molecules in the gaseous and the
liquid state are the same--which we may call the supposition of the
identity of the two conditions of aggregation--then the heat which is
given out by the condensation at constant T is due to the potential
energy lost in consequence of the coming closer of the molecules which
attract each other, and then it is equal to a(1/v_l - 1/v_v). If a should
be a function of the temperature, it follows from thermodynamics that it
would be equal to (a - T.da/dT)(1/v_l - 1/v_v). Not only in the case of
liquid and gas, but always when the volume is diminished, a quantity of
heat is given out equal to a(1/v1 - 1/v2) or (a -T.da/dT)(1/v1 - 1/v2).
Associating substances.
If, however, when the volume is diminished at a given temperature, and
also during the transition from the gaseous to the liquid state,
combination into larger molecule-complexes takes place, the total
internal heat may be considered as the sum of that which is caused by
the combination of the molecules into greater molecule-complexes and by
their approach towards each other. We have the simplest case of possible
greater complexity when two molecules combine to one. From the course of
the changes in the density of the vapour we assume that this occurs,
e.g. with nitrogen peroxide, NO2, and acetic acid, and the somewhat
close agreement of the observed density of the vapour with that which is
calculated from the hypothesis of such an association to
double-molecules, makes this supposition almost a certainty. In such
cases the molecules in the much denser liquid state must therefore be
considered as double-molecules, either completely so or in a variable
degree depending on the temperature. The given equation of state cannot
hold for such substances. Even though we assume that a and b are not
modified by the formation of double-molecules, yet RT is modified, and,
since it is proportional to the number of the molecules, is diminished
by the combination. The laws found for normal substances will,
therefore, not hold for such associating substances. Accordingly for
substances for which we have already found an anormal density of the
vapour, we cannot expect the general laws for the liquid state, which
have been treated above, to hold good without modification, and in many
respects such substances will therefore not follow the law of
corresponding states. There are, however, also substances of which the
anormal density of vapour has not been stated, and which yet cannot be
ranged under this law, e.g. water and alcohols. The most natural thing,
of course, is to ascribe the deviation of these substances, as of the
others, to the fact that the molecules of the liquid are polymerized. In
this case we have to account for the following circumstance, that
whereas for NO2 and acetic acid in the state of saturated vapour the
degree of association increases if the temperature falls, the reverse
must take place for water and alcohols. Such a difference may be
accounted for by the difference in the quantity of heat released by the
polymerization to double-molecules or larger molecule-complexes. The
quantity of heat given out when two molecules fall together may be
calculated for NO2 and acetic acid from the formula of Gibbs for the
density of vapour, and it proves to be very considerable. With this the
following fact is closely connected. If in the pv diagram, starting from
a point indicating the state of saturated vapour, a geometrical locus is
drawn of the points which have the same degree of association, this
curve, which passes towards isothermals of higher T if the volume
diminishes, requires for the same change in T a greater diminution of
volume than is indicated by the border-curve. For water and alcohols
this geometrical locus will be found on the other side of the
border-curve, and the polymerization heat will be small, i.e. smaller
than the latent heat. For substances with a small polymerization heat
the degree of association will continually decrease if we move along the
border-curve on the side of the saturated vapour in the direction
towards lower T. With this, it is perfectly compatible that for such
substances the saturated vapour, e.g. under the pressure of one
atmosphere, should show an almost normal density. Saturated vapour of
water at 100 deg. has a density which seems nearly 4% greater than the
theoretical one, an amount which is greater than can be ascribed to the
deviation from the gas-laws. For the relation between v, T, and x, if x
represents the fraction of the number of double-molecules, the following
formula has been found ("Moleculartheorie," _Zeits. Phys. Chem._, 1890,
vol. v):
x(v - b) 2(E1 - E2)
log --------- = ---------- + C,
(1 - x)^2 R1T
from which
T /dv\ E1 - E2
------( -- ) = -2-------,
(v - b) \dT/_x R1T
which may elucidate what precedes.
Condensation of substances with low Tc.
By far the majority of substances have a value of Tc above the ordinary
temperature, and diminution of volume (increase of pressure) is
sufficient to condense such gaseous substances into liquids. If Tc is
but little above the ordinary temperature, a great increase of pressure
is in general required to effect condensation. Substances for which Tc
is much higher than the ordinary temperature T0, e.g. Tc > 5/3 T0, occur
as liquids, even without increase of pressure; that is, at the pressure
of one atmosphere. The value 5/3 is to be considered as only a mean
value, because of the inequality of p_c. The substances for which Tc is
smaller than the ordinary temperature are but few in number. Taking the
temperature of melting ice as a limit, these gases are in successive
order: CH4, NO, O2, CO, N2 and H2 (the recently discovered gases argon,
helium, &c., are left out of account). If these gases are compressed at
0 deg. centigrade they do not show a trace of liquefaction, and therefore
they were long known under the name of "permanent gases." The discovery,
however, of the critical temperature carried the conviction that these
substances would not be "permanent gases" if they were compressed at
much lower T. Hence the problem arose how "low temperatures" were to be
brought about. Considered from a general point of view the means to
attain this end may be described as follows: we must make use of the
above-mentioned circumstance that heat disappears when a substance
expands, either with or without performing external work. According as
this heat is derived from the substance itself which is to be condensed,
or from the substance which is used as a means of cooling, we may divide
the methods for condensing the so-called permanent gases into two
principal groups.
Liquids as means of cooling.
In order to use a liquid as a cooling bath it must be placed in a
vacuum, and it must be possible to keep the pressure of the vapour in
that space at a small value. According to the boiling-law, the
temperature of the liquid must descend to that at which the maximum
tension of the vapour is equal to the pressure which reigns on the
surface of the liquid. If the vapour, either by means of absorption or
by an air-pump, is exhausted from the space, the temperature of the
liquid and that of the space itself depend upon the value of the
pressure which finally prevails in the space. From a practical point of
view the value of T3 may be regarded as the limit to which the
temperature falls. It is true that if the air is exhausted to the utmost
possible extent, the temperature may fall still lower, but when the
substance has become solid, a further diminution of the pressure in the
space is of little advantage. At any rate, as a solid body evaporates
only on the surface, and solid gases are bad conductors of heat, further
cooling will only take place very slowly, and will scarcely neutralize
the influx of heat. If the pressure p3 is very small, it is perhaps
practically impossible to reach T3; if so, T3 in the following lines
will represent the temperature practically attainable. There is thus for
every gas a limit below which it is not to be cooled further, at least
not in this way. If, however, we can find another gas for which the
critical temperature is sufficiently above T3 of the first chosen gas,
and if it is converted into a liquid by cooling with the first gas, and
then treated in the same way as the first gas, it may in its turn be
cooled down to (T3)2. Going on in this way, continually lower
temperatures may be attained, and it would be possible to condense all
gases, provided the difference of the successive critical temperatures
of two gases fulfils certain conditions. If the ratio of the absolute
critical temperatures for two gases, which succeed one another in the
series, should be sensibly greater than 2, the value of T3 for the first
gas is not, or not sufficiently, below the Tc of the second gas. This is
the case when one of the gases is nitrogen, on which hydrogen would
follow as second gas. Generally, however, we shall take atmospheric air
instead of nitrogen. Though this mixture of N2 and O2 will show other
critical phenomena than a simple substance, yet we shall continue to
speak of a Tc for air, which is given at -140 deg. C., and for which,
therefore, Tc amounts to 133 deg. absolute. The lowest T which may be
expected for air in a highly rarefied space may be evaluated at 60 deg.
absolute--a value which is higher than the Tc for hydrogen. Without new
contrivances it would, accordingly, not be possible to reach the
critical temperature of H2. The method by which we try to obtain
successively lower temperatures by making use of successive gases is
called the "cascade method." It is not self-evident that by sufficiently
diminishing the pressure on a liquid it may be cooled to such a degree
that the temperature will be lowered to T3, if the initial temperature
was equal to Tc, or but little below it, and we can even predict with
certainty that this will not be the case for all substances. It is
possible, too, that long before the triple point is reached the whole
liquid will have evaporated. The most favourable conditions will, of
course, be attained when the influx of heat is reduced to a minimum. As
a limiting case we imagine the process to be isentropic. Now the
question has become, Will an isentropic line, which starts from a point
of the border-curve on the side of the liquid not far from the
critical-point, remain throughout its descending course in the
heterogeneous region, or will it leave the region on the side of the
vapour? As early as 1878 van der Waals (_Verslagen Kon. Akad.
Amsterdam_) pointed out that the former may be expected to be the case
only for substances for which c_p/c_v is large, and the latter for those
for which it is small; in other words, the former will take place for
substances the molecules of which contain few atoms, and the latter for
substances the molecules of which contain many atoms. Ether is an
example of the latter class, and if we say that the quantity h (specific
heat of the saturated vapour) for ether is found to be positive, we
state the same thing in other words. It is not necessary to prove this
theorem further here, as the molecules of the gases under consideration
contain only two atoms and the total evaporation of the liquid is not to
be feared.
In the practical application of this cascade-method some variation is
found in the gases chosen for the successive stages. Thus methyl
chloride, ethylene and oxygen are used in the cryogenic laboratory of
Leiden, while Sir James Dewar has used air as the last term. Carbonic
acid is not to be recommended on account of the comparatively high value
of T3. In order to prevent loss of gas a system of "circulation" is
employed. This method of obtaining low temperatures is decidedly
laborious, and requires very intricate apparatus, but it has the great
advantage that very _constant_ low temperatures may be obtained, and can
be regulated arbitrarily within pretty wide limits.
Cooling by expansion.
In order to lower the temperature of a substance down to T3, it is not
always necessary to convert it first into the liquid state by means of
another substance, as was assumed in the last method for obtaining low
temperatures. Its own expansion is sufficient, provided the initial
condition be properly chosen, and provided we take care, even more than
in the former method, that there is no influx of heat. Those conditions
being fulfilled, we may, simply by adiabatic expansion, not only lower
the temperature of some substances down to T3, but also convert them
into the liquid state. This is especially the case with substances the
molecules of which contain few atoms.
Let us imagine the whole net of isothermals for homogeneous phases drawn
in a pv diagram, and in it the border-curve. Within this border-curve,
as in the heterogeneous region, the theoretical part of every isothermal
must be replaced by a straight line. The isothermals may therefore be
divided into two groups, viz. those which keep outside the heterogeneous
region, and those which cross this region. Hence an isothermal,
belonging to the latter group, enters the heterogeneous region on the
liquid side, and leaves it at the same level on the vapour side. Let us
imagine in the same way all the isentropic curves drawn for homogeneous
states. Their form resembles that of isothermals in so far as they show
a maximum and a minimum, if the entropy-constant is below a certain
value, while if it is above this value, both the maximum and the minimum
disappear, the isentropic line in a certain point having at the same
time dp/dv and d^2p/dv^2 = 0 for this particular value of the constant.
This point, which we might call the critical point of the isentropic
lines, lies in the heterogeneous region, and therefore cannot be
realized, since as soon as an isentropic curve enters this region its
theoretical part will be replaced by an empiric part. If an isentropic
curve crosses the heterogeneous region, the point where it enters this
region must, just as for the isothermals, be connected with the point
where it leaves the region by another curve. When c_p/c_v = k (the
limiting value of c_p/c_v for infinite rarefaction is meant) approaches
unity, the isentropic curves approach the isothermals and vice versa. In
the same way the critical point of the isentropic curves comes nearer to
that of the isothermals. And if k is not much greater than 1, e.g. k <
1.08, the following property of the isothermals is also preserved, viz.
that an isentropic curve, which enters the heterogeneous region on the
side of the liquid, leaves it again on the side of the vapour, not of
course at the same level, but at a lower point. If, however, k is
greater, and particularly if it is so great as it is with molecules of
one or two atoms, an isentropic curve, which enters on the side of the
liquid, however far prolonged, always remains within the heterogeneous
region. But in this case all isentropic curves, if sufficiently
prolonged, will enter the heterogeneous region. Every isentropic curve
has one point of intersection with the border-curve, but only a small
group intersect the border-curve in three points, two of which are to be
found not far from the top of the border-curve and on the side of the
vapour. Whether the sign of h (specific heat of the saturated vapour) is
negative or positive, is closely connected with the preceding facts. For
substances having k great, h will be negative if T is low, positive if T
rises, while it will change its sign again before Tc is reached. The
values of T, at which change of sign takes place, depend on k. The law
of corresponding states holds good for this value of T for all
substances which have the same value of k.
Now the gases which were considered as permanent are exactly those for
which k has a high value. From this it would follow that every adiabatic
expansion, provided it be sufficiently continued, will bring such
substances into the heterogeneous region, i.e. they can be condensed by
adiabatic expansion. But since the final pressure must not fall below a
certain limit, determined by experimental convenience, and since the
quantity which passes into the liquid state must remain a fraction as
large as possible, and since the expansion never can take place in such
a manner that no heat is given out by the walls or the surroundings, it
is best to choose the initial condition in such a way that the
isentropic curve of this point cuts the border-curve in a point on the
side of the liquid, lying as low as possible. The border-curve being
rather broad at the top, there are many isentropic curves which
penetrate the heterogeneous region under a pressure which differs but
little from p_c. Availing himself of this property, K. Olszewski has
determined p_c for hydrogen at 15 atmospheres. Isentropic curves, which
lie on the right and on the left of this group, will show a point of
condensation at a lower pressure. Olszewski has investigated this for
those lying on the right, but not for those on the left.
From the equation of state (p + a/v^2)(v-b) = RT, the equation of the
isentropic curve follows as (p + a/v^2)(v-b)^k = C, and from this we may
deduce T(v - b)^(k-1) = C'. This latter relation shows in how high a
degree the cooling depends on the amount by which k surpasses unity, the
change in v - b being the same.
What has been said concerning the relative position of the border-curve
and the isentropic curve may be easily tested for points of the
border-curve which represent rarefied gaseous states, in the following
way. Following the border-curve we found before [int]' Tc/T for the
value of T/p.dp/dT. Following the isentropic curve the value of T/p
dp/dT is equal to k/(k - 1). If k/(k - 1) < [int]'Tc/T, the isentropic
curve rises more steeply than the border-curve. If we take f' = 7 and
choose the value of Tc/2 for T--a temperature at which the saturated
vapour may be considered to follow the gas-laws--then k/(k - 1) = 14, or
k = 1.07 would be the limiting value for the two cases. At any rate k =
1.41 is great enough to fulfil the condition, even for other values of
T. Cailletet and Pictet have availed themselves of this adiabatic
expansion for condensing some permanent gases, and it must also be used
when, in the cascade method, T3 of one of the gases lies above Tc of the
next.
Linde's apparatus.
A third method of condensing the permanent gases is applied in C. P. G.
Linde's apparatus for liquefying air. Under a high pressure p1 a current
of gas is conducted through a narrow spiral, returning through another
spiral which surrounds the first. Between the end of the first spiral
and the beginning of the second the current of gas is reduced to a much
lower pressure p2 by passing through a tap with a fine orifice. On
account of the expansion resulting from this sudden decrease of
pressure, the temperature of the gas, and consequently of the two
spirals, falls sensibly. If this process is repeated with another
current of gas, this current, having been cooled in the inner spiral,
will be cooled still further, and the temperature of the two spirals
will become still lower. If the pressures p1 and p2 remain constant the
cooling will increase with the lowering of the temperature. In Linde's
apparatus this cycle is repeated over and over again, and after some
time (about two or three hours) it becomes possible to draw off liquid
air.
The cooling which is the consequence of such a decrease of pressure was
experimentally determined in 1854 by Lord Kelvin (then Professor W.
Thomson) and Joule, who represent the result of their experiments in the
formula
p1 - p2
T1 - T2 = [gamma]-------.
T^2
In their experiments p2 was always 1 atmosphere, and the amount of p1
was not large. It would, therefore, be certainly wrong, even though for
a small difference in pressure the empiric formula might be
approximately correct, without closer investigation to make use of it
for the differences of pressure used in Linde's apparatus, where p1 =
200 and p2 = 18 atmospheres. For the existence of a most favourable
value of p1 is in contradiction with the formula, since it would follow
from it that T1 - T2 would always increase with the increase of p1. Nor
would it be right to regard as the cause for the existence of this most
favourable value of p1 the fact that the heat produced in the
compression of the expanded gas, and therefore p1/p2, must be kept as
small as possible, for the simple reason that the heat is produced in
quite another part of the apparatus, and might be neutralized in
different ways.
Closer examination of the process shows that if p2 is given, a most
favourable value of p1 must exist for the cooling itself. If p1 is taken
still higher, the cooling decreases again; and we might take a value for
p1 for which the cooling would be zero, or even negative.
If we call the energy per unit of weight [epsilon] and the specific
volume v, the following equation holds:--
[epsilon]1 + p1v1 - p2v2 = [epsilon]2,
or [epsilon]1 + p1v1 = [epsilon]2 + p2v2.
According to the symbols chosen by Gibbs, [chi]1 = [chi]2.
As [chi]1 is determined by T1 and p1, and [chi]2 by T2 and p2, we
obtain, if we take T1 and p2 as being constant,
/[delta][chi]1\ /[delta][chi]2\
(---------------) dp1 = ( ------------- ) dT2.
\ [delta]p1 /_T1 \ [delta]T2 /_p2
If T_2 is to have a minimum value, we have
/[delta][chi]1\ /[delta][chi]1)\
(---------------) = 0, or ( -------------- ) = 0.
\ [delta]p1 /_T1 \ [delta]v1 /_T1
From this follows
/[delta][epsilon]1\ /[delta](p1v1)\
( ----------------- ) + ( ------------- ) = 0.
\ [delta]v1 /_T1 \ [delta]v1 /_T1
As ([delta][epsilon]1/[delta]v1)T is positive, we shall have to take
for the maximum cooling such a pressure that the product p_v decreases
with v, viz. a pressure larger than that at which p_v has the minimum
value. By means of the equation of state mentioned already, we find
for the value of the specific volume that gives the greatest cooling
the formula
RT1b 2a
---------- = ----,
(v1 - b)^2 v1^2
and for the value of the pressure
_ _____ _ _ _____ _
| / 4 T1 | | / 4 T1 |
p1 = 27p_c | 1 - / -- -- | | 3 / -- -- - 1 |.
|_ \/ 27 Tc _| |_ \/ 27 Tc _|
If we take the value 2Tc for T1, as we may approximately for air when
we begin to work with the apparatus, we find for p1 about 8p_c, or
more than 300 atmospheres. If we take T1 = Tc, as we may at the end of
the process, we find p1 = 2.5p_c, or 100 atmospheres. The constant
pressure which has been found the most favourable in Linde's apparatus
is a mean of the two calculated pressures. In a theoretically perfect
apparatus we ought, therefore, to be able to regulate p1 according to
the temperature in the inner spiral.
The critical temperatures and pressures of the permanent gases are given
in the following table, the former being expressed on the absolute scale
and the latter in atmospheres:--
Tc p_c Tc p_c
CH4 191.2 deg. 55 CO 133.5 deg. 35.5
NO 179.5 deg. 71.2 N2 127 deg. 35
O2 155 deg. 50 Air 133 deg. 39
Argon 152 deg. 50.6 H2 32 deg. 15
The values of Tc and p_c for hydrogen are those of Dewar. They are in
approximate accordance with those given by K. Olszewski. Liquid hydrogen
was first collected by J. Dewar in 1898. Apparatus for obtaining
moderate and small quantities have been described by M. W. Travers and
K. Olszewski. H. Kamerlingh Onnes at Leiden has brought about a
circulation yielding more than 3 litres per hour, and has made use of it
to keep baths of 1.5 litre capacity at all temperatures between 20.2
deg. and 13.7 deg. absolute, the temperatures remaining constant within
0.01 deg. (See also LIQUID GASES.) (J. D. v. d. W.)
CONDENSER, the name given to many forms of apparatus which have for
their object the concentration of matter, or bringing it into a smaller
volume, or the intensification of energy. In chemistry the word is
applied to an apparatus which cools down, or condenses, a vapour to a
liquid; reference should be made to the article DISTILLATION for the
various types in use, and also to GAS (_Gas Manufacture_) and COAL TAR;
the device for the condensation of the exhaust steam of a steam-engine
is treated in the article STEAM-ENGINE. In woollen manufactures,
"condensation" of the wool is an important operation and is accomplished
by means of a "condenser." The term is also given--generally as a
qualification, e.g. condensing-syringe, condensing-pump,--to apparatus
by which air or a vapour may be compressed. In optics a "condenser" is a
lens, or system of lenses, which serves to concentrate or bring the
luminous rays to a focus; it is specially an adjunct to the optical
lantern and microscope. In electrostatics a condenser is a device for
concentrating an electrostatic charge (see ELECTROSTATICS; LEYDEN JAR;
ELECTROPHORUS).
CONDER, CHARLES (1868-1909), English artist, son of a civil engineer,
was born in London, and spent his early years in India. After an English
education he went into the government service in Australia, but in 1890
determined to devote himself to art, and studied for several years in
Paris, where in 1893 he became an associate of the Societe Nationale des
Beaux-Arts. About 1895 his reputation as an original painter,
particularly of Watteau-like designs for fans, spread among a limited
circle of artists in London, mainly connected first with the New English
Art Club, and later the International Society; and his unique and
charming decorative style, in dainty pastoral scenes, gradually gave him
a peculiar vogue among connoisseurs. Examples of his work were bought
for the Luxembourg and other art galleries. Conder suffered much in
later years from ill-health, and died on the 9th of February 1909.
CONDILLAC, ETIENNE BONNOT DE (1715-1780), French philosopher, was born
at Grenoble of a legal family on the 30th of September 1715, and, like
his elder brother, the well-known political writer, abbe de Mably, took
holy orders and became abbe de Mureau.[1] In both cases the profession
was hardly more than nominal, and Condillac's whole life, with the
exception of an interval as tutor at the court of Parma, was devoted to
speculation. His works are _Essai sur l'origine des connaissances
humaines_ (1746), _Traite des systemes_ (1749), _Traite des sensations_
(1754), _Traite des animaux_ (1755), a comprehensive _Cours d'etudes_
(1767-1773) in 13 vols., written for the young Duke Ferdinand of Parma,
a grandson of Louis XV., _Le Commerce et le gouvernement, consideres
relativement l'un a l'autre_ (1776), and two posthumous works, _Logique_
(1781) and the unfinished _Langue des calculs_ (1798). In his earlier
days in Paris he came much into contact with the circle of Diderot. A
friendship with Rousseau, which lasted in some measure to the end, may
have been due in the first instance to the fact that Rousseau had been
domestic tutor in the family of Condillac's uncle, M. de Mably, at
Lyons. Thanks to his natural caution and reserve, Condillac's relations
with unorthodox philosophers did not injure his career; and he justified
abundantly the choice of the French court in sending him to Parma to
educate the orphan duke, then a child of seven years. In 1768, on his
return from Italy, he was elected to the French Academy, but attended no
meeting after his reception. He spent his later years in retirement at
Flux, a small property which he had purchased near Beaugency, and died
there on the 3rd of August 1780.
Though Condillac's genius was not of the highest order, he is important
both as a psychologist and as having established systematically in
France the principles of Locke, whom Voltaire had lately made
fashionable. In setting forth his empirical sensationism, Condillac
shows many of the best qualities of his age and nation, lucidity,
brevity, moderation and an earnest striving after logical method.
Unfortunately it must be said of him as of so many of his
contemporaries, "er hat die Theile in seiner Hand, fehlt leider nur der
geistiger Band"; in the analysis of the human mind on which his fame
chiefly rests, he has missed out the active and spiritual side of human
experience. His first book, the _Essai sur l'origine des connaissances
humaines_, keeps close to his English master. He accepts with some
indecision Locke's deduction of our knowledge from two sources,
sensation and reflection, and uses as his main principle of explanation
the association of ideas. His next book, the _Traite des systemes_, is a
vigorous criticism of those modern systems which are based upon abstract
principles or upon unsound hypotheses. His polemic, which is inspired
throughout with the spirit of Locke, is directed against the innate
ideas of the Cartesians, Malebranche's faculty--psychology, Leibnitz's
monadism and preestablished harmony, and, above all, against the
conception of substance set forth in the first part of the _Ethics_ of
Spinoza. By far the most important of his works is the _Traite des
sensations_, in which he emancipates himself from the tutelage of Locke
and treats psychology in his own characteristic way. He had been led, he
tells us, partly by the criticism of a talented lady, Mademoiselle
Ferrand, to question Locke's doctrine that the senses give us intuitive
knowledge of objects, that the eye, for example, judges naturally of
shapes, sizes, positions and distances. His discussions with the lady
had convinced him that to clear up such questions it was necessary to
study our senses separately, to distinguish precisely what ideas we owe
to each sense, to observe how the senses are trained, and how one sense
aids another. The result, he was confident, would show that all human
faculty and knowledge are transformed sensation only, to the exclusion
of any other principle, such as reflection. The plan of the book is that
the author imagines a statue organized inwardly like a man, animated by
a soul which has never received an idea, into which no sense-impression
has ever penetrated. He then unlocks its senses one by one, beginning
with smell, as the sense that contributes least to human knowledge. At
its first experience of smell, the consciousness of the statue is
entirely occupied by it; and this occupancy of consciousness is
attention. The statue's smell-experience will produce pleasure or pain;
and pleasure and pain will thenceforward be the master-principle which,
determining all the operations of its mind, will raise it by degrees to
all the knowledge of which it is capable. The next stage is memory,
which is the lingering impression of the smell-experience upon the
attention: "memory is nothing more than a mode of feeling." From memory
springs comparison: the statue experiences the smell, say, of a rose,
while remembering that of a carnation; and "comparison is nothing more
than giving one's attention to two things simultaneously." And "as soon
as the statue has comparison it has judgment." Comparisons and judgments
become habitual, are stored in the mind and formed into series, and thus
arises the powerful principle of the association of ideas. From
comparison of past and present experiences in respect of their
pleasure-giving quality arises desire; it is desire that determines the
operation of our faculties, stimulates the memory and imagination, and
gives rise to the passions. The passions, also, are nothing but
sensation transformed. These indications will suffice to show the
general course of the argument in the first section of the _Traite des
sensations_. To show the thoroughness of the treatment it will be enough
to quote the headings of the chief remaining chapters: "Of the Ideas of
a Man limited to the Sense of Smell," "Of a Man limited to the Sense of
Hearing," "Of Smell and Hearing combined," "Of Taste by itself, and of
Taste combined with Smell and Hearing," "Of a Man limited to the Sense
of Sight." In the second section of the treatise Condillac invests his
statue with the sense of touch, which first informs it of the existence
of external objects. In a very careful and elaborate analysis, he
distinguishes the various elements in our tactile experiences--the
touching of one's own body, the touching of objects other than one's own
body, the experience of movement, the exploration of surfaces by the
hands: he traces the growth of the statue's perceptions of extension,
distance and shape. The third section deals with the combination of
touch with the other senses. The fourth section deals with the desires,
activities and ideas of an isolated man who enjoys possession of all the
senses; and ends with observations on a "wild boy" who was found living
among bears in the forests of Lithuania. The conclusion of the whole
work is that in the natural order of things everything has its source in
sensation, and yet that this source is not equally abundant in all men;
men differ greatly in the degree of vividness with which they feel; and,
finally, that man is nothing but what he has acquired; all innate
faculties and ideas are to be swept away. The last dictum suggests the
difference that has been made to this manner of psychologizing by modern
theories of evolution and heredity.
Condillac's work on politics and history, contained, for the most part,
in his _Cours d'etudes_, offers few features of interest, except so far
as it illustrates his close affinity to English thought: he had not the
warmth and imagination to make a good historian. In logic, on which he
wrote extensively, he is far less successful than in psychology. He
enlarges with much iteration, but with few concrete examples, upon the
supremacy of the analytic method; argues that reasoning consists in the
substitution of one proposition for another which is identical with it;
and lays it down that science is the same thing as a well-constructed
language, a proposition which in his _Langue des calculs_ he tries to
prove by the example of arithmetic. His logic has in fact the good and
bad points that we might expect to find in a sensationist who knows no
science but mathematics. He rejects the medieval apparatus of the
syllogism; but is precluded by his standpoint from understanding the
active, spiritual character of thought; nor had he that interest in
natural science and appreciation of inductive reasoning which form the
chief merit of J. S. Mill. It is obvious enough that Condillac's
anti-spiritual psychology, with its explanation of personality as an
aggregate of sensations, leads straight to atheism and determinism.
There is, however, no reason to question the sincerity with which he
repudiates both these consequences. What he says upon religion is always
in harmony with his profession; and he vindicated the freedom of the
will in a dissertation that has very little in common with the _Traite
des sensations_ to which it is appended. The common reproach of
materialism should certainly not be made against him. He always asserts
the substantive reality of the soul; and in the opening words of his
_Essai_, "Whether we rise to heaven, or descend to the abyss, we never
get outside ourselves--it is always our own thoughts that we perceive,"
we have the subjectivist principle that forms the starting-point of
Berkeley.
As was fitting to a disciple of Locke, Condillac's ideas have had most
importance in their effect upon English thought. In matters connected
with the association of ideas, the supremacy of pleasure and pain, and
the general explanation of all mental contents as sensations or
transformed sensations, his influence can be traced upon the Mills and
upon Bain and Herbert Spencer. And, apart from any definite
propositions, Condillac did a notable work in the direction of making
psychology a science; it is a great step from the desultory, genial
observation of Locke to the rigorous analysis of Condillac,
short-sighted and defective as that analysis may seem to us in the light
of fuller knowledge. His method, however, of imaginative reconstruction
was by no means suited to English ways of thinking. In spite of his
protests against abstraction, hypothesis and synthesis, his allegory of
the statue is in the highest degree abstract, hypothetical and
synthetic. James Mill, who stood more by the study of concrete
realities, put Condillac into the hands of his youthful son with the
warning that here was an example of what to avoid in the method of
psychology. In France Condillac's doctrine, so congenial to the tone of
18th century philosophism, reigned in the schools for over fifty years,
challenged only by a few who, like Maine de Biran, saw that it gave no
sufficient account of volitional experience. Early in the 19th century,
the romantic awakening of Germany had spread to France, and sensationism
was displaced by the eclectic spiritualism of Victor Cousin.
Condillac's collected works were published in 1798 (23 vols.) and two
or three times subsequently; the last edition (1822) has an
introductory dissertation by A. F. Thery. The _Encyclopedie
methodique_ has a very long article on Condillac (Naigeon).
Biographical details and criticism of the _Traite des systemes_ in J.
P. Damiron's _Memoires pour servir a l'histoire de la philosophie au
dixhuitieme siecle_, tome iii.; a full criticism in V. Cousin's _Cours
de l'histoire de la philosophie moderne_, ser. i. tome iii. Consult
also F. Rethore, _Condillac ou l'empirisme et le rationalisme_ (1864);
L. Dewaule, _Condillac et la psychologie anglaise contemporaine_
(1891); histories of philosophy. (H. St.)
FOOTNOTE:
[1] i.e. abbot _in commendam_ of the Premonstratensian abbey of Mureau
in the Vosges. (Ed.)
CONDITION (Lat. _condicio_, from _condicere_, to agree upon, arrange;
not connected with _conditio_, from _condere, conditum_, to put
together), a stipulation, agreement. The term is applied technically to
any circumstance, action or event which is regarded as the indispensable
prerequisite of some other circumstance, action or event. It is also
applied generally to the sum of the circumstances in which a person is
situated, and more specifically to favourable or prosperous
circumstances; thus a person of wealth or birth is described as a person
"of condition," or an athlete as being "in condition," i.e. physically
fit, having gone through the necessary course of preliminary training.
In all these senses there is implicit the idea of limitation or
restraint imposed with a view to the attainment of a particular end.
(1) _In Logic_, the term "condition" is closely related to "cause" in so
far as it is applied to prior events, &c., in the absence of which
another event would not take place. It is, however, different from
"cause" inasmuch as it has a predominantly negative or passive
significance. Hence the adjective "conditional" is applied to
propositions in which the truth of the main statement is made to depend
on the truth of another; these propositions are distinguished from
categorical propositions, which simply state a fact, as being "composed
of two categorical propositions united by a conjunction," e.g. if A is
B, C is D. The second statement (the "consequent") is restricted or
qualified by the first (the "antecedent"). By some logicians these
propositions are classified as (1) Hypothetical, and (2) Disjunctive,
and their function in syllogistic reasoning gives rise to the following
classification of conditional arguments:--(a) Constructive hypothetical
syllogism (_modus ponens_, "affirmative mood"): If A is B, C is D; but A
is B; therefore C is D. (b) Destructive hypothetical syllogism (_modus
tollens_, mood which "removes," i.e. the consequent): if A is B, C is D;
but C is not D; therefore A is not B. In (a) the antecedent must be
affirmed, in (b) the consequent must be denied; otherwise the arguments
become fallacious. A second class of conditional arguments are
disjunctive syllogisms consisting of (c) the _modus ponendo tollens_: A
is either B or C; but A is B; therefore C is not D; and (d) _modus
tollendo ponens_: A is either B or C; A is not B; therefore A is C. A
more complicated conditional argument is the dilemma (q.v.).[1]
The limiting or restrictive significance of "condition" has led to its
use in metaphysical theory in contradistinction to the conception of
absolute being, the _aseitas_ of the Schoolmen. Thus all finite things
exist in certain relations not only to all other things but also to
thought; in other words, all finite existence is "conditioned." Hence
Sir Wm. Hamilton speaks of the "philosophy of the unconditioned," i.e.
of thought in distinction to things which are determined by thought in
relation to other things. An analogous distinction is made (cf. H. W. B.
Joseph, _Introduction to Logic_, pp. 380 foll.) between the so-called
universal laws of nature and conditional principles, which, though they
are regarded as having the force of law, are yet dependent or
derivative, i.e. cannot be treated as universal truths. Such principles
hold good under present conditions, but other conditions might be
imagined under which they would be invalid; they hold good only as
corollaries from the laws of nature under existing conditions.
(2) _In Law_, condition in its general sense is a restraint annexed to a
thing, so that by the non-performance the party to it shall receive
prejudice and loss, and by the performance commodity or advantage.
Conditions may be either: (1) condition in a deed or _express_
condition, i.e. the condition being expressed in actual words; or (2)
condition in law or _implied_ condition, i.e. where, although no
condition is actually expressed, the law implies a condition. The word
is also used indifferently to mean either the event upon the happening
of which some estate or obligation is to begin or end, or the provision
or stipulation that the estate or obligation will depend upon the
happening of the event. A condition may be of several kinds: (1) a
condition _precedent_, where, for example, an estate is granted to one
for life upon condition that, if the grantee pay the grantor a certain
sum on such a day, he shall have the fee simple; (2) a condition
_subsequent_, where, for example, an estate is granted in fee upon
condition that the grantee shall pay a certain sum on a certain day, or
that his estate shall cease. Thus a condition precedent gets or gains,
while a condition subsequent keeps and continues. A condition may also
be _affirmative_, that is, the doing of an act; _negative_, the not
doing of an act; _restrictive, compulsory_, &c. The word is also used
adjectivally in the sense set out above, as in the phrases "conditional
legacy," "conditional limitation," "conditional promise," &c.; that is,
the legacy, the limitation, the promise is to take effect only upon the
happening of a certain event.
FOOTNOTE:
[1] The terminology used above has not been adopted by all logicians.
"Conditional" has been used as equivalent to "hypothetical" in the
widest sense (including "disjunctive"); or narrowed down to be
synonymous with "conjunctive" (the condition being there more
explicit), as a subdivision of "hypothetical."
CONDITIONAL FEE, at English common law, a fee or estate restrained in
its form of donation to some particular heirs, as, to the heirs of a
man's body, or to the heirs male of his body. It was called a
conditional fee by reason of the condition expressed or implied in the
donation of it, that if the donee died without such particular heirs,
the land should revert to the donor. In other words, it was a fee simple
on condition that the donee had issue, and as soon as such issue was
born, the estate was supposed to become absolute by the performance of
the condition. A conditional fee was converted by the statute _De Donis
Conditionalibus_ into an estate tail (see REAL PROPERTY).
CONDITIONAL LIMITATION, in law, a phrase used in two senses. (1) The
qualification annexed to the grant of an estate or interest in land,
providing for the determination of that grant or interest upon a
particular contingency happening. An estate with such a limitation can
endure only until the particular contingency happens; it is a present
interest, to be divested on a future contingency. The grant of an estate
to a man so long as he is parson of Dale, or while he continues
unmarried, are instances of conditional limitations of estates for life.
(2) A future use or interest in land limited to take effect upon a given
contingency. For instance, a grant to N. and his heirs to the use of A.,
provided that when C. returns from Rome the land shall go to the use of
B. in fee simple. B. is said to take under a conditional limitation,
operating by executory devise or springing or shifting use (see
REMAINDER, REVERSION).
CONDOM, a town of south-western France, capital of an arrondissement in
the department of Gers, on the right bank of the Baise, at its junction
with the Gele, 27 m. by road N.N.W. of Auch. Pop. (1906) town, 4046;
commune, 6435. Two stone bridges unite Condom with its suburb on the
left bank of the river. The streets are small and narrow and several old
houses still remain, but to the east the town is bordered by pleasant
promenades. The Gothic church of St Pierre, its chief building, was
erected from 1506 to 1521, and was till 1790 a cathedral. The interior,
which is without aisles or transept, is surrounded by lateral chapels.
On the south is a beautifully sculptured portal. An adjoining cloister
of the 16th century is occupied by the hotel de ville. The former
episcopal palace with its graceful Gothic chapel is used as a law-court.
The sub-prefecture, a tribunal of first instance, and a communal
college, are among the public institutions. Brandy-distilling,
wood-sawing, iron-founding and the manufacture of stills are among the
industries. The town is a centre for the sale of Armagnac brandy and has
commerce in grain and flour, much of which is river-borne.
Condom (_Condomus_) was founded in the 8th century, but in 840 was
sacked and burnt by the Normans. A monastery built here c. 900 by the
wife of Sancho of Gascony was soon destroyed by fire, but in 1011 was
rebuilt, by Hugh, bishop of Agen. Round this abbey the town grew up, and
in 1317 was made into an episcopal see by Pope John XXII. The line of
bishops, which included Bossuet (1668-1671), came to an end in 1790 when
the see was suppressed. Condom was, during the middle ages, a fortress
of considerable strength. During the Hundred Years' War, after several
unsuccessful attempts, it was finally captured and held by the English.
In 1569 it was sacked by the Huguenots under Gabriel, count of
Montgomery.
A list of monographs, &c., on the abbey, see and town of Condom is
given s.v. in U. Chevalier, _Repertoire des sources. Topobibliogr_.
(Montbeliard, 1894-1899).
CONDOR (_Sarcorhamphus gryphus_), an American vulture, and almost the
largest of existing birds of flight, although by no means attaining the
dimensions attributed to it by early writers. It usually measures about
4 ft. from the point of the beak to the extremity of the tail, and 9 ft.
between the tips of its wings, while it is probable that the expanse of
wing never exceeds 12 ft. The head and neck are destitute of feathers,
and the former, which is much flattened above, is in the male crowned
with a caruncle or comb, while the skin of the latter in the same sex
lies in folds, forming a wattle. The adult plumage is of a uniform
black, with the exception of a frill of white feathers nearly
surrounding the base of the neck, and certain wing feathers which,
especially in the male, have large patches of white. The middle toe is
greatly elongated, and the hinder one but slightly developed, while the
talons of all the toes are comparatively straight and blunt, and are
thus of little use as organs of prehension. The female, contrary to the
usual rule among birds of prey, is smaller than the male.
The condor is a native of South America, where it is confined to the
region of the Andes, from the Straits of Magellan to 4 deg. north
latitude,--the largest examples, it is said, being found about the
volcano of Cayambi, situated on the equator. It is often seen on the
shores of the Pacific, especially during the rainy season, but its
favourite haunts for roosting and breeding are at elevations of 10,000
to 16,000 ft. There, during the months of February and March, on
inaccessible ledges of rock, it deposits two white eggs, from 3 to 4 in.
in length, its nest consisting merely of a few sticks placed around the
eggs. The period of incubation lasts for seven weeks, and the young are
covered with a whitish down until almost as large as their parents. They
are unable to fly till nearly two years old, and continue for a
considerable time after taking wing to roost and hunt with their
parents. The white ruff on the neck, and the similarly coloured feathers
of the wing, do not appear until the completion of the first moulting.
By preference the condor feeds on carrion, but it does not hesitate to
attack sheep, goats and deer, and for this reason it is hunted down by
the shepherds, who, it is said, train their dogs to look up and bark at
the condors as they fly overhead. They are exceedingly voracious, a
single condor of moderate size having been known, according to Orton, to
devour a calf, a sheep and a dog in a single week. When thus gorged with
food, they are exceedingly stupid, and may then be readily caught. For
this purpose a horse or mule is killed, and the carcase surrounded with
palisades to which the condors are soon attracted by the prospect of
food, for the weight of evidence seems to favour the opinion that those
vultures owe their knowledge of the presence of carrion more to sight
than to scent. Having feasted themselves to excess, they are set upon by
the hunters with sticks, and being unable, owing to the want of space
within the pen, to take the run without which they are unable to rise on
wing, they are readily killed or captured. They sleep during the greater
part of the day, searching for food in the clearer light of morning and
evening. They are remarkably heavy sleepers, and are readily captured by
the inhabitants ascending the trees on which they roost, and noosing
them before they awaken. Great numbers of condors are thus taken alive,
and these, in certain districts, are employed in a variety of
bull-fighting. They are exceedingly tenacious of life, and can exist, it
is said, without food for over forty days. Although the favourite haunts
of the condor are at the level of perpetual snow, yet it rises to a much
greater height, Humboldt having observed it flying over Chimborazo at a
height of over 23,000 ft. On wing the movements of the condor, as it
wheels in majestic circles, are remarkably graceful. The birds flap
their wings on rising from the ground, but after attaining a moderate
elevation they seem to sail on the air, Charles Darwin having watched
them for half an hour without once observing a flap of their wings.
CONDORCET, MARIE JEAN ANTOINE NICOLAS CARITAT, MARQUIS DE (1743-1794),
French mathematician, philosopher and Revolutionist, was born at
Ribemont, in Picardy, on the 17th of September 1743. He descended from
the ancient family of Caritat, who took their title from Condorcet, near
Nyons in Dauphine, where they were long settled. His father dying while
he was very young, his mother, a very devout woman, had him educated at
the Jesuit College in Reims and at the College of Navarre in Paris,
where he displayed the most varied mental activity. His first public
distinctions were gained in mathematics. At the age of sixteen his
performances in analysis gained the praise of D'Alembert and A. C.
Clairaut, and at the age of twenty-two he wrote a treatise on the
integral calculus which obtained warm approbation from competent judges.
With his many-sided intellect and richly-endowed emotional nature,
however, it was impossible for him to be a specialist, and least of all
a specialist in mathematics. Philosophy and literature attracted him,
and social work was dearer to him than any form of intellectual
exercise. In 1769 he became a member of the Academy of Sciences. His
contributions to its memoirs are numerous, and many of them are on the
most abstruse and difficult mathematical problems.
Being of a very genial, susceptible and enthusiastic disposition, he was
the friend of almost all the distinguished men of his time, and a
zealous propagator of the religious and political views then current
among the literati of France. D'Alembert, Turgot and Voltaire, for whom
he had great affection and veneration, and by whom he was highly
respected and esteemed, contributed largely to the formation of his
opinions. His _Lettre d'un laboureur de Picardie a M. N..._ (Necker) was
written under the inspiration of Turgot, in defence of free internal
trade in corn. Condorcet also wrote on the same subject the _Reflexions
sur le commerce des bles_ (1776). His _Lettre d'un theologien_, &c., was
attributed to Voltaire, being inspired throughout by the Voltairian
anti-clerical spirit. He was induced by D'Alembert to take an active
part in the preparation of the _Encyclopedie_. His _Eloges des
Academiciens de l'Academie Royale des Sciences morts depuis 1666
jusqu'en 1699_ (1773) gained him the reputation of being an eloquent and
graceful writer. He was elected to the perpetual secretaryship of the
Academy of Sciences in 1777, and to the French Academy in 1782. He was
also member of the academies of Turin, St Petersburg, Bologna and
Philadelphia. In 1785 he published his _Essai sur l'application de
l'analyse aux probabilites des decisions prises a la pluralite des
voix_,--a remarkable work which has a distinguished place in the history
of the doctrine of probability; a second edition, greatly enlarged and
completely recast, appeared in 1804 under the title of _Elements du
calcul des probabilites et son application aux jeux de hazard, a la
loterie, et aux jugements des hommes, &c._ In 1786 he married Sophie de
Grouchy, a sister of Marshal Grouchy, said to have been one of the most
beautiful women of her time. Her _salon_ at the Hotel des Monnaies,
where Condorcet lived in his capacity as inspector-general of the mint,
was one of the most famous of the time. In 1786 Condorcet published his
_Vie de Turgot_, and in 1787 his _Vie de Voltaire_. Both works were
widely and eagerly read, and are perhaps, from a merely literary point
of view, the best of Condorcet's writings.
The political tempest which had been long gathering over France now
began to break and to carry everything before it. Condorcet was, of
course, at once hurried along by it into the midst of the conflicts and
confusion of the Revolution. He greeted with enthusiasm the advent of
democracy, and laboured hard to secure and hasten its triumph. He was
indefatigable in writing pamphlets, suggesting reforms, and planning
constitutions. He was not a member of the States-General of 1789, but he
had expressed his ideas in the electoral assembly of the noblesse of
Mantes. The first political functions which he exercised were those of a
member of the municipality of Paris (1790). He was next chosen by the
Parisians to represent them in the Legislative Assembly, and then
appointed by that body one of its secretaries. In this capacity he drew
up most of its addresses, but seldom spoke, his pen being more effective
than his tongue. He was the chief author of the address to the European
powers when they threatened France with war. He was keenly interested in
education, and, as a member of the committee of public instruction,
presented to the Assembly (April 21 and 22, 1792) a bold and
comprehensive scheme for the organization of a system of state education
which, though more urgent questions compelled its postponement, became
the basis of that adopted by the Convention, and thus laid the
foundations on which the modern system of national education in France
is built up. After the attempted flight of the king, in June 1791,
Condorcet was one of the first to declare in favour of a republic, and
it was he who drew up the memorandum which led the Assembly, on the 4th
of September 1792, to decree the suspension of the king and the
summoning of the National Convention. He had, meanwhile, resigned his
offices and left the Hotel des Monnaies; his declaration in favour of
republicanism had alienated him from his former friends of the
constitutional party, and he did not join the Jacobin Club, which had
not yet declared against the monarchy. Though attached to no powerful
political group, however, his reputation gave him great influence. At
the elections for the Convention he was chosen for five departments, and
took his seat for that of Aisne. He now became the most influential
member of the committee on the constitution, and as "reporter" he
drafted and presented to the Convention (February 15, 1793) a
constitution, which was, however, after stormy debates, rejected in
favour of that presented by Herault de Sechelles. The work of
constitution-making had been interrupted by the trial of Louis XVI.
Condorcet objected to the assumption of judicial functions by the
Convention, objected also on principle to the infliction of the death
penalty; but he voted the king guilty of conspiring against liberty and
worthy of any penalty short of death, and against the appeal to the
people advocated by the Girondists. In the atmosphere of universal
suspicion that inspired the Terror his independent attitude could not,
however, be maintained with impunity. His severe and public criticism of
the constitution adopted by the Convention, his denunciation of the
arrest of the Girondists, and his opposition to the violent conduct of
the Mountain, led to his being accused of conspiring against the
Republic. He was condemned and declared to be _hors la loi_. Friends,
sought for him an asylum in the house of Madame Vernet, widow of the
sculptor and a near connexion of the painters of the same name. Without
even asking his name, this heroic woman, as soon as she was assured that
he was an honest man, said, "Let him come, and lose not a moment, for
while we talk he may be seized." When the execution of the Girondists
showed him that his presence exposed his protectress to a terrible
danger, he resolved to seek a refuge elsewhere. "I am outlawed," he
said, "and if I am discovered you will meet the same sad end as myself.
I must not stay." Madame Vernet's reply deserves to be immortal, and
should be given in her own words: "La Convention, Monsieur, a le droit
de mettre hors la loi: elle n'a pas le pouvoir de mettre hors de
l'humanite; vous resterez." From that time she had his movements
strictly watched lest he should attempt to quit her house. It was partly
to turn his mind from the idea of attempting this, by occupying it
otherwise, that his wife and some of his friends, with the co-operation
of Madame Vernet, prevailed on him to engage in the composition of the
work by which he is best known--the _Esquisse d'un tableau historique
des progres de l'esprit humain_. In his retirement Condorcet wrote also
his justification, and several small works, such as the _Moyen
d'apprendre a compter surement et avec facilite_, which he intended for
the schools of the republic. Several of these works were published at
the time, thanks to his friends; the rest appeared after his death.
Among the latter was the admirable _Avis d'un proscrit a sa fille_.
While in hiding he also continued to take an active interest in public
affairs. Thus, he wrote several important memoranda on the conduct of
the war against the Coalition, which were laid before the Committee of
Public Safety anonymously by a member of the Mountain named Marcoz, who
lived in the same house as Condorcet without thinking it his duty to
denounce him. In the same way he forwarded to Arbogast, president of the
committee for public instruction, the solutions of several problems in
higher mathematics.
Certain circumstances having led him to believe that the house of Madame
Vernet, 21 rue Servandoni, was suspected and watched by his enemies,
Condorcet, by a fatally successful artifice, at last baffled the
vigilance of his generous friend and escaped. Disappointed in finding
even a night's shelter at the chateau of one whom he had befriended, he
had to hide for three days and nights in the thickets and stone-quarries
of Clamart. Oh the evening of the 7th of April 1794--not, as Carlyle
says, on a "bleared May morning,"--with garments torn, with wounded leg,
with famished looks, he entered a tavern in the village named, and
called for an omelette. "How many eggs in your omelette?" "A dozen."
"What is your trade?" "A carpenter." "Carpenters have not hands like
these, and do not ask for a dozen eggs in an omelette." When his papers
were demanded he had none to show; when his person was searched a Horace
was found on him. The villagers seized him, bound him, haled him
forthwith on bleeding feet towards Bourg-la-Reine; he fainted by the
way, was set on a horse offered in pity by a passing peasant, and, at
the journey's end, was cast into a cold damp cell. Next morning he was
found dead on the floor. Whether he had died from suffering and
exhaustion, from apoplexy or from poison, is an undetermined question.
Condorcet was undoubtedly a most sincere, generous and noble-minded man.
He was eager in the pursuit of truth, ardent in his love of human good,
and ever ready to undertake labour or encounter danger on behalf of the
philanthropic plans which his fertile mind contrived and his benevolent
heart inspired. It was thus that he worked for the suppression of
slavery, for the rehabilitation of the chevalier de La Barre, and in
defence of Lally-Tollendal. He lived at a time when calumny was rife,
and various slanders were circulated regarding him, but fortunately the
slightest examination proves them to have been inexcusable fabrications.
That while openly opposing royalty he was secretly soliciting the office
of tutor to the Dauphin; that he was accessory to the murder of the duc
de la Rochefoucauld; or that he sanctioned the burning of the literary
treasures of the learned congregations, are stories which can be shown
to be utterly untrue.
His philosophical fame is chiefly associated with the _Esquisse ...
des'progres_ mentioned above. With the vision of the guillotine before
him, with confusion and violence around him, he comforted himself by
trying to demonstrate that the evils of life had arisen from a
conspiracy of priests and rulers against their fellows, and from the bad
laws and institutions which they had succeeded in creating, but that the
human race would finally conquer its enemies and free itself of its
evils. His fundamental idea is that of a human perfectibility which has
manifested itself in continuous progress in the past, and must lead to
indefinite progress in the future. He represents man as starting from
the lowest stage of barbarism, with no superiority over the other
animals save that of bodily organization, and as advancing
uninterruptedly, at a more or less rapid rate, in the path of
enlightenment, virtue and happiness. The stages which the human race has
already gone through, or, in other words, the great epochs of history,
are regarded as nine in number. The first three can confessedly be
described only conjecturally from general observations as to the
development of the human faculties, and the analogies of savage life. In
the first epoch, men are united into hordes of hunters and fishers, who
acknowledge in some degree public authority and the claims of family
relationship, and who make use of an articulate language. In the second
epoch--the pastoral state--property is introduced, and along with it
inequality of conditions, and even slavery, but also leisure to
cultivate intelligence, to invent some of the simpler arts, and to
acquire some of the more elementary truths of science. In the third
epoch--the agricultural state--as leisure and wealth are greater, labour
better distributed and applied, and the means of communication increased
and extended, progress is still more rapid. With the invention of
alphabetic writing the conjectural part of history closes, and the more
or less authenticated part commences. The fourth and fifth epochs are
represented as corresponding to Greece and Rome. The middle ages are
divided into two epochs, the former of which terminates with the
Crusades, and the latter with the invention of printing. The eighth
epoch extends from the invention of printing to the revolution in the
method of philosophic thinking accomplished by Descartes. And the ninth
epoch begins with that great intellectual revolution, and ends with the
great political and moral revolution of 1789, and is illustrious,
according to Condorcet, through the discovery of the true system of the
physical universe by Newton, of human nature by Locke and Condillac, and
of society by Turgot, Richard Price and Rousseau. There is an epoch of
the future--a tenth epoch,--and the most original part of Condorcet's
treatise is that which is devoted to it. After insisting that general
laws regulative of the past warrant general inferences as to the future,
he argues that the three tendencies which the entire history of the past
shows will be characteristic features of the future are:--(1) the
destruction of inequality between nations; (2) the destruction of
inequality between classes; and (3) the improvement of individuals, the
indefinite perfectibility of human nature itself--intellectually,
morally and physically. These propositions have been much misunderstood.
The equality to which he represents nations and individuals as tending
is not absolute equality, but equality of freedom and of rights. It is
that equality which would make the inequality of the natural advantages
and faculties of each community and person beneficial to all. Nations
and men, he thinks, are equal, if equally free, and are all tending to
equality because all tending to freedom. As to indefinite
perfectibility, he nowhere denies that progress is conditioned both by
the constitution of humanity and the character of its surroundings. But
he affirms that these conditions are compatible with endless progress,
and that the human mind can assign no fixed limits to its own
advancement in knowledge and virtue, or even to the prolongation of
bodily life. This theory explains the importance he attached to popular
education, to which he looked for all sure progress.
The book is pervaded by a spirit of excessive hopefulness, and contains
numerous errors of detail, which are fully accounted for by the
circumstances in which it was written. Its value lies entirely in its
general ideas. Its chief defects spring from its author's narrow and
fanatical aversion to all philosophy which did not attempt to explain
the world exclusively on mechanical and sensational principles, to all
religion whatever, and especially to Christianity and Christian
institutions, and to monarchy. His ethical position, however, gives
emphasis to the sympathetic impulses and social feelings, and had
considerable influence upon Auguste Comte.
Madame de Condorcet (b. 1764), who was some twenty years younger than
her husband, was rendered penniless by his proscription, and compelled
to support not only herself and her four years old daughter but her
younger sister, Charlotte de Grouchy. After the end of the Jacobin
Terror she published an excellent translation of Adam Smith's _Theory of
Moral Sentiments_; in 1798 a work of her own, _Lettres sur la
sympathie_; and in 1799 her husband's _Eloges des academiciens_. Later
she co-operated with Cabanis, who had married her sister, and with Garat
in publishing the complete works of Condorcet (1801-1804). She adhered
to the last to the political views of her husband, and under the
Consulate and Empire her _salon_ became a meeting-place of those opposed
to the autocratic regime. She died at Paris on the 8th of September
1822. Her daughter was married, in 1807, to General O'Connor.
A _Biographie de Condorcet_, by M. F. Arago, is prefixed to A.
Condorcet-O'Connor's edition of Condorcet's works, in 12 volumes
(1847-1849). There is an able essay on Condorcet in Lord Morley of
Blackburn's _Critical Miscellanies_. On Condorcet as an historical
philosopher see Comte's _Cours de philosophie positive_, iv. 252-253,
and _Systeme de politique positive_, iv. Appendice General, 109-111;
F. Laurent, _Etudes_, xii. 121-126, 89-110; and R. Flint, _Philosophy
of History in France and Germany_, i. 125-138. The _Memoires de
Condorcet sur la Revolution francaise, extraits de sa correspondance
et de celles de ses amis_ (2 vols., Paris, Ponthieu, 1824), which were
in fact edited by F. G. de la Rochefoucauld-Liancourt, are spurious.
See also Dr J. F. E. Robinet, _Condorcet, sa vie et son [oe]uvre_, and
more especially L. Cahen, _Condorcet et la Revolution francaise_
(Paris, 1904). On Madame de Condorcet see Antoine Guillois, _La
Marquise de Condorcet, sa famille, son salon et ses [oe]uvres_ (Paris,
1897).
CONDOTTIERE (plural, _condottieri_), an Italian term, derived ultimately
from Latin _conducere_, meaning either "to conduct" or "to hire," for
the leader of the mercenary military companies, often several thousand
strong, which used to be hired out to carry on the wars of the Italian
states. The word is often extended so as to include the soldiers as well
as the leader of a company. The condottieri played a very important part
in Italian history from the middle of the 13th to the middle of the 15th
century. The special political and military circumstances of medieval
Italy, and in particular the wars of the Guelphs and Ghibellines,
brought it about that the condottieri and their leaders played a more
conspicuous and important part in history than the "Free Companies"
elsewhere. Amongst these circumstances the absence of a numerous feudal
cavalry, the relative luxury of city life, and the incapacity of city
militia for wars of aggression were the most prominent. From this it
resulted that war was not merely the trade of the condottiere, but also
his monopoly, and he was thus able to obtain whatever terms he asked,
whether money payments or political concessions. These companies were
recruited from wandering mercenary bands and individuals of all nations,
and from the ranks of the many armies of middle Europe which from time
to time overran Italy.
Montreal d'Albarno, a gentleman of Provence, was the first to give them
a definite form. A severe discipline and an elaborate organization were
introduced within the company itself, while in their relations to the
people the most barbaric licence was permitted. Montreal himself was put
to death at Rome by Rienzi, and Conrad Lando succeeded to the command.
The Grand Company, as it was called, soon numbered about 7000 cavalry
and 1500 select infantry, and was for some years the terror of Italy.
They seem to have been Germans chiefly. On the conclusion (1360) of the
peace of Bretigny between England and France, Sir John Hawkwood (q.v.)
led an army of English mercenaries, called the White Company, into
Italy, which took a prominent part in the confused wars of the next
thirty years. Towards the end of the century the Italians began to
organize armies of the same description. This ended the reign of the
purely mercenary company, and began that of the semi-national mercenary
army which endured in Europe till replaced by the national standing army
system. The first company of importance raised on the new basis was that
of St George, originated by Alberigo, count of Barbiano, many of whose
subordinates and pupils conquered principalities for themselves. Shortly
after, the organization of these mercenary armies was carried to the
highest perfection by Sforza Attendolo, condottiere in the service of
Naples, who had been a peasant of the Romagna, and by his rival
Brancaccio di Montone in the service of Florence. The army and the
renown of Sforza were inherited by his son Francesco Sforza, who
eventually became duke of Milan (1450). Less fortunate was another great
condottiere, Carmagnola, who first served one of the Visconti, and then
conducted the wars of Venice against his former masters, but at last
awoke the suspicion of the Venetian oligarchy, and was put to death
before the palace of St Mark (1432). Towards the end of the 15th
century, when the large cities had gradually swallowed up the small
states, and Italy itself was drawn into the general current of European
politics, and became the battlefield of powerful armies--French, Spanish
and German--the condottieri, who in the end proved quite unequal to the
gendarmerie of France and the improved troops of the Italian states,
disappeared.
The soldiers of the condottieri were almost entirely heavy armoured
cavalry (men-at-arms). They had, at any rate before 1400, nothing in
common with the people among whom they fought, and their disorderly
conduct and rapacity seem often to have exceeded that of other medieval
armies. They were always ready to change sides at the prospect of higher
pay. They were connected with each other by the interest of a common
profession, and by the possibility that the enemy of to-day might be the
friend and fellow-soldier of to-morrow. Further, a prisoner was always
more valuable than a dead enemy. In consequence of all this their
battles were often as bloodless as they were theatrical. Splendidly
equipped armies were known to fight for hours with hardly the loss of a
man (Zagonara, 1423; Molinella, 1467).