VOLUME VI SLICE VII Columbus to Condottiere (continued 10)

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 Liquids as means of cooling. 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° C., and for which, therefore, Tc amounts to 133° absolute. The lowest T which may be expected for air in a highly rarefied space may be evaluated at 60° 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 cp/cv 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.

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. Cooling by expansion. 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 d²p/dv² = 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 cp/cv = k (the limiting value of cp/cv 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 pc. Availing himself of this property, K. Olszewski has determined pc 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/v²)(v-b) = RT, the equation of the isentropic curve follows as (p + a/v²)(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 ∫′ (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) < ∫′ (Tc/T), the isentropic curve rises more steeply than the border-curve. If we take ∫′ = 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.

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 Linde’s apparatus. 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

T1-T2 = γ p1 - p2 .

T²

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 ε and the specific volume v, the following equation holds:—

ε1 + p1v1 - p2v2 = ε2,

or

ε1 + p1v1 = ε2 + p2v2.

According to the symbols chosen by Gibbs, χ1 = χ2.

As χ1 is determined by T1 and p1, and χ2 by T2 and p2, we obtain, if we take T1 and p2 as being constant,

( δχ1 ) dp1 = ( δχ2 ) dT2.

δp1 T1 δT1 p2

If T2 is to have a minimum value, we have

( δχ1 ) = 0 or ( δχ1 ) = 0.

δp1 T1 δv1 T1

From this follows

( δε1 ) + [ δ(p1v1) ] = 0.

δv1 T1 δv1 T1

As (δε1/δv1)T is positive, we shall have to take for the maximum cooling such a pressure that the product pv decreases with v, viz. a pressure larger than that at which pv 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 v1²

and for the value of the pressure

p1 = 27 pc[1 - √ 4 T1 ] [3 √ 4 T1 - 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 8pc, or more than 300 atmospheres. If we take T1 = Tc, as we may at the end of the process, we find p1 = 2.5pc, 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 pc Tc pc

CH4 191.2° 55 CO 133.5° 35.5

NO 179.5° 71.2 N2 127° 35

O2 155° 50 Air 133° 39

Argon 152° 50.6 H2 32° 15

The values of Tc and pc 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° and 13.7° absolute, the temperatures remaining constant within 0.01°. (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 Société 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, ÉTIENNE 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, abbé de Mably, took holy orders and became abbé 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), Traité des systèmes (1749), Traité des sensations (1754), Traité des animaux (1755), a comprehensive Cours d’études (1767-1773) in 13 vols., written for the young Duke Ferdinand of Parma, a grandson of Louis XV., Le Commerce et le gouvernement, considérés relativement l’un à 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 Traité des systèmes, 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 Traité 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 Traité 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’études, 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 Traité 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. Théry. The Encyclopédie méthodique has a very long article on Condillac (Naigeon). Biographical details and criticism of the Traité des systèmes in J. P. Damiron’s Mémoires pour servir à l’histoire de la philosophie au dixhuitième siècle, tome iii.; a full criticism in V. Cousin’s Cours de l’histoire de la philosophie moderne, ser. i. tome iii. Consult also F. Rethoré, Condillac ou l’empirisme et le rationalisme (1864); L. Dewaule, Condillac et la psychologie anglaise contemporaine (1891); histories of philosophy.

(H. St.)

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.

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 Baïse, at its junction with the Gèle, 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 hôtel 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, Répertoire des sources. Topobibliogr. (Montbéliard, 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° 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 Dauphiné, 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 à 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 Réflexions sur le commerce des blés (1776). His Lettre d’un théologien, &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 Encyclopédie. His Éloges des Académiciens de l’Académie 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 probabilités des décisions prises à la pluralité 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 Éléments du calcul des probabilités et son application aux jeux de hazard, à 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 Hôtel 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 Hôtel 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 Hérault de Séchelles. 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’humanité; 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 progrès de l’esprit humain. In his retirement Condorcet wrote also his justification, and several small works, such as the Moyen d’apprendre à compter sûrement et avec facilitê, 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 à 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 château 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’progrès 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 Éloges des acadêmiciens. 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 régime. 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 Système de politique positive, iv. Appendice Général, 109-111; F. Laurent, Études, xii. 121-126, 89-110; and R. Flint, Philosophy of History in France and Germany, i. 125-138. The Mémoires de Condorcet sur la Révolution française, 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 œuvre, and more especially L. Cahen, Condorcet et la Révolution française (Paris, 1904). On Madame de Condorcet see Antoine Guillois, La Marquise de Condorcet, sa famille, son salon et ses œuvres (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).