The explanation of the rings, suggested by Young, and developed by Herschel, refers them to interference between one portion of light scattered or diffracted by a particle of dust, and then regularly refracted and reflected, and another portion first regularly refracted and reflected and then diffracted at emergence by the same particle. It has been shown by Stokes (Camb. Trans., 1851, 9, p. 147) that no regular interference is to be expected between portions of light diffracted by different particles of dust.In the memoir of Stokes will be found a very complete discussion of the whole subject, and to this the reader must be referred who desires a fuller knowledge. Our limits will not allow us to do more than touch upon one or two points. The condition of fixity of the rings when observed in air, and of distinctness when a screen is used, is that the systems due to all parts of the diffusing surface should coincide; and it is fulfilled only when, as in Newton’s experiments, the source and screen are in the plane passing through the centre of curvature of the glass.Fig. 5.As the simplest for actual calculation, we will consider a little further the case where the glass is plane and parallel, of thickness t and index μ, and is supplemented by a lens at whose focus the source of light is placed. This lens acts both as collimator and as object-glass, so that the combination of lens and plane mirror replaces the concave mirror of Newton’s experiment. The retardation is calculated in the same way as for thin plates. In fig. 5 the diffracting particle is situated at B, and we have to find the relative retardation of the two rays which emerge finally at inclination θ, the one diffracted at emergence following the path ABDBIE, and the other diffracted at entrance and following the path ABFGH. The retardation of the former from B to I is 2μt + BI, and of the latter from B to the equivalent place G is 2μBF. Now FB = t sec θ′, θ′ being the angle of refraction; BI = 2t tan θ′sin θ; so that the relative retardation F is given byR = 2μt {1 + μ−1tan θ′ sin θ − sec θ′) = 2μt (1 − cos θ′).If θ, θ′ be small, we may takeR = 2tθ2/ μ(1).as sufficiently approximate.The condition of distinctness is here satisfied, since R is the same for every ray emergent parallel to a given one. The rays of one parallel system are collected by the lens to a focus at a definite point in the neighbourhood of the original source.The formula (1) was discussed by Herschel, and shown to agree with Newton’s measures. The law of formation of the rings follows immediately from the expression for the retardation, the radius of the ring of nthorder being proportional to n and to the square root of the wave-length.
The explanation of the rings, suggested by Young, and developed by Herschel, refers them to interference between one portion of light scattered or diffracted by a particle of dust, and then regularly refracted and reflected, and another portion first regularly refracted and reflected and then diffracted at emergence by the same particle. It has been shown by Stokes (Camb. Trans., 1851, 9, p. 147) that no regular interference is to be expected between portions of light diffracted by different particles of dust.
In the memoir of Stokes will be found a very complete discussion of the whole subject, and to this the reader must be referred who desires a fuller knowledge. Our limits will not allow us to do more than touch upon one or two points. The condition of fixity of the rings when observed in air, and of distinctness when a screen is used, is that the systems due to all parts of the diffusing surface should coincide; and it is fulfilled only when, as in Newton’s experiments, the source and screen are in the plane passing through the centre of curvature of the glass.
As the simplest for actual calculation, we will consider a little further the case where the glass is plane and parallel, of thickness t and index μ, and is supplemented by a lens at whose focus the source of light is placed. This lens acts both as collimator and as object-glass, so that the combination of lens and plane mirror replaces the concave mirror of Newton’s experiment. The retardation is calculated in the same way as for thin plates. In fig. 5 the diffracting particle is situated at B, and we have to find the relative retardation of the two rays which emerge finally at inclination θ, the one diffracted at emergence following the path ABDBIE, and the other diffracted at entrance and following the path ABFGH. The retardation of the former from B to I is 2μt + BI, and of the latter from B to the equivalent place G is 2μBF. Now FB = t sec θ′, θ′ being the angle of refraction; BI = 2t tan θ′sin θ; so that the relative retardation F is given by
R = 2μt {1 + μ−1tan θ′ sin θ − sec θ′) = 2μt (1 − cos θ′).
If θ, θ′ be small, we may take
R = 2tθ2/ μ
(1).
as sufficiently approximate.
The condition of distinctness is here satisfied, since R is the same for every ray emergent parallel to a given one. The rays of one parallel system are collected by the lens to a focus at a definite point in the neighbourhood of the original source.
The formula (1) was discussed by Herschel, and shown to agree with Newton’s measures. The law of formation of the rings follows immediately from the expression for the retardation, the radius of the ring of nthorder being proportional to n and to the square root of the wave-length.
§ 10.Interferometer.—In many cases it is necessary that the two rays ultimately brought to interference should be sufficiently separated over a part of their course to undergo a different treatment; for example, it may be desired to pass them through different gases.
A simple modification of Young’s original experiment suffices to solve this problem. Light proceeding from a slit at A (fig. 6) perpendicular to the plane of the paper, falls upon a collimating lens B whose aperture is limited by two parallel and rather narrow slits of equal width. The parallel rays CE, DF (shown broken in the figure) transmitted by these slits are brought to a focus at G by the lens EF where they form an image of the original slit A. This image is examined with an eye-piece of high magnifying power. The interference bands at G undergo displacement if the rays CE, DF are subjected to a relative retardation. Consider what happens at the point G, which is the geometrical image of A. If all is symmetrical so that the paths CE, DF are equal, there is brightness. But if, for example, CE be subjected to a relative retardation of half a wave-length, the brightness is replaced by darkness, and the bands are shifted through half a band-interval.An apparatus of this kind has been found suitable for determining the refractivity of gases, especially of gases available only in small quantities (Proc. Roy. Soc., 1896, 59, p. 198; 1898, 64, p. 95). There is great advantage in replacing the ordinary eye-piece by a simple cylindrical magnifier formed of a glass rod 4 mm. in diameter. Under these conditions a paraffin lamp sufficed to illuminate the slit at A, and allowed the refractivities of gases to be compared to about one-thousandth part.If the object be to merely see the bands in full development the lenses of the above apparatus may be dispensed with. A metal or pasteboard tube 10 in. long carries at one end a single slit (analogous to A) and at the other a double slit (analogous to C, D). This double slit, which requires to be very fine, may be made by scraping two parallel lines with a knife on a piece of silvered glass. The tube is pointed to a bright light, and the eye, held close behind the double slit, is focused upon the far slit.§ 11.Other Refractometers.—In another form of refractometer, employed by J. C. Jamin, the separations are effected by reflections at the surfaces of thick plates. Two thick glass mirrors, exactly the same in all respects, are arranged as in fig. 7. The first of the two interfering rays is that which is reflected at the first surface of the first reflector and at the second surface of the second reflector. The second ray undergoes reflection at the second surface of the first reflector and at the first surface of the second reflector. Uponthe supposition that the plates are parallel and equally thick, the paths pursued by these two rays are equal. P represents a thin plate of glass interposed in the path of one ray, by which the bands are shifted.Fig. 8.In Jamin’s apparatus the two rays which produce interference are separated by a distance proportional to the thickness of the mirrors, and since there is a practical limit to this thickness, it is not possible to separate the two rays very far. In A. A. Michelson’s interferometer there is no such restriction. “The light starts from source S (fig. 8) and separates at the rear of plate A, part of it being reflected to the plane mirror C, returning exactly, on its path through A, to O, where it may be observed by a telescope or received upon a screen. The other part of the ray goes through the glass plate A, passes through B, and is reflected by the plane mirror D, returns on its path to the starting point A, where it is reflected so as nearly to coincide with the first ray. The plane parallel glass B is introduced to compensate for the extra thickness of glass which the first ray has traversed in passing twice through the plate A. Without it the two paths would not be optically identical, because the first would contain more glass than the second. Some light is reflected from the front surface of the plate A, but its effect may be rendered insignificant by covering the rear surface of A with a coating of silver of such thickness that about equal portions of the incident light are reflected and transmitted. The plane parallel plates A and B are worked originally in one piece, which is afterwards cut in two. The two pieces are placed parallel to one another, thus ensuring exact equality in the two optical paths AC and AD” (see Michelson,Light-Waves and their Uses, Chicago, 1903).The adjustments of this apparatus are very delicate. Of the fully silvered mirrors C, D, the latter must be accurately parallel to the image of the former. For many purposes one of the mirrors, C, must be capable of movement parallel to itself, usually requiring the use of very truly constructed ways. An escape from this difficulty may be found in the employment of a layer of mercury, standing on copper, the surface of which automatically assumes the horizontal position.Michelson’s apparatus, employed to view an extended field of homogeneous light, exhibits Haidinger’s rings, and if all is in good order the dark parts are sensibly black. As the order of interference increases, greater and greater demand is made upon the homogeneity of the light. Thus, if the illumination be from a sodium flame, the rings are at first distinct, but as the difference of path increases the duplicity of the bright sodium line begins to produce complications. After 500 rings, the bright parts of one system coincide with the dark parts of the other (Fizeau), and if the two systems were equally bright all trace of rings would disappear. A little later the rings would again manifest themselves and, after 1000 had gone by, would be nearly or quite as distinct as at first. And these alternations of distinctness and indistinctness would persist until the point was reached at which even a single sodium line was insufficiently homogeneous. Conversely, the changes ofvisibilityof the rings as the difference of path increases give evidence as to the duplicity of the line. In this way Michelson obtained important information as to the constitution of the approximately homogeneous lines obtained from electrical discharge through attenuated metallic vapours. Especially valuable is the vacuum tube containing cadmium. The red line proved itself to be single and narrow in a high degree, and the green line was not far behind.But although in Michelson’s hands the apparatus has done excellent spectroscopic work, it is not without its weak points. A good deal of labour is required to interpret the visibility curves, and in some cases the indications are actually ambiguous. For instance, it is usually impossible to tell on which side of the principal component a feebler companion lies. It would seem that for spectroscopic purposes this apparatus must yield to that of Fabry and Pérot, in which multiple reflections are utilized; this is a spectroscope in the literal sense, inasmuch as the constitution of a spectrum line is seen by simple inspection.
A simple modification of Young’s original experiment suffices to solve this problem. Light proceeding from a slit at A (fig. 6) perpendicular to the plane of the paper, falls upon a collimating lens B whose aperture is limited by two parallel and rather narrow slits of equal width. The parallel rays CE, DF (shown broken in the figure) transmitted by these slits are brought to a focus at G by the lens EF where they form an image of the original slit A. This image is examined with an eye-piece of high magnifying power. The interference bands at G undergo displacement if the rays CE, DF are subjected to a relative retardation. Consider what happens at the point G, which is the geometrical image of A. If all is symmetrical so that the paths CE, DF are equal, there is brightness. But if, for example, CE be subjected to a relative retardation of half a wave-length, the brightness is replaced by darkness, and the bands are shifted through half a band-interval.
An apparatus of this kind has been found suitable for determining the refractivity of gases, especially of gases available only in small quantities (Proc. Roy. Soc., 1896, 59, p. 198; 1898, 64, p. 95). There is great advantage in replacing the ordinary eye-piece by a simple cylindrical magnifier formed of a glass rod 4 mm. in diameter. Under these conditions a paraffin lamp sufficed to illuminate the slit at A, and allowed the refractivities of gases to be compared to about one-thousandth part.
If the object be to merely see the bands in full development the lenses of the above apparatus may be dispensed with. A metal or pasteboard tube 10 in. long carries at one end a single slit (analogous to A) and at the other a double slit (analogous to C, D). This double slit, which requires to be very fine, may be made by scraping two parallel lines with a knife on a piece of silvered glass. The tube is pointed to a bright light, and the eye, held close behind the double slit, is focused upon the far slit.
§ 11.Other Refractometers.—In another form of refractometer, employed by J. C. Jamin, the separations are effected by reflections at the surfaces of thick plates. Two thick glass mirrors, exactly the same in all respects, are arranged as in fig. 7. The first of the two interfering rays is that which is reflected at the first surface of the first reflector and at the second surface of the second reflector. The second ray undergoes reflection at the second surface of the first reflector and at the first surface of the second reflector. Uponthe supposition that the plates are parallel and equally thick, the paths pursued by these two rays are equal. P represents a thin plate of glass interposed in the path of one ray, by which the bands are shifted.
In Jamin’s apparatus the two rays which produce interference are separated by a distance proportional to the thickness of the mirrors, and since there is a practical limit to this thickness, it is not possible to separate the two rays very far. In A. A. Michelson’s interferometer there is no such restriction. “The light starts from source S (fig. 8) and separates at the rear of plate A, part of it being reflected to the plane mirror C, returning exactly, on its path through A, to O, where it may be observed by a telescope or received upon a screen. The other part of the ray goes through the glass plate A, passes through B, and is reflected by the plane mirror D, returns on its path to the starting point A, where it is reflected so as nearly to coincide with the first ray. The plane parallel glass B is introduced to compensate for the extra thickness of glass which the first ray has traversed in passing twice through the plate A. Without it the two paths would not be optically identical, because the first would contain more glass than the second. Some light is reflected from the front surface of the plate A, but its effect may be rendered insignificant by covering the rear surface of A with a coating of silver of such thickness that about equal portions of the incident light are reflected and transmitted. The plane parallel plates A and B are worked originally in one piece, which is afterwards cut in two. The two pieces are placed parallel to one another, thus ensuring exact equality in the two optical paths AC and AD” (see Michelson,Light-Waves and their Uses, Chicago, 1903).
The adjustments of this apparatus are very delicate. Of the fully silvered mirrors C, D, the latter must be accurately parallel to the image of the former. For many purposes one of the mirrors, C, must be capable of movement parallel to itself, usually requiring the use of very truly constructed ways. An escape from this difficulty may be found in the employment of a layer of mercury, standing on copper, the surface of which automatically assumes the horizontal position.
Michelson’s apparatus, employed to view an extended field of homogeneous light, exhibits Haidinger’s rings, and if all is in good order the dark parts are sensibly black. As the order of interference increases, greater and greater demand is made upon the homogeneity of the light. Thus, if the illumination be from a sodium flame, the rings are at first distinct, but as the difference of path increases the duplicity of the bright sodium line begins to produce complications. After 500 rings, the bright parts of one system coincide with the dark parts of the other (Fizeau), and if the two systems were equally bright all trace of rings would disappear. A little later the rings would again manifest themselves and, after 1000 had gone by, would be nearly or quite as distinct as at first. And these alternations of distinctness and indistinctness would persist until the point was reached at which even a single sodium line was insufficiently homogeneous. Conversely, the changes ofvisibilityof the rings as the difference of path increases give evidence as to the duplicity of the line. In this way Michelson obtained important information as to the constitution of the approximately homogeneous lines obtained from electrical discharge through attenuated metallic vapours. Especially valuable is the vacuum tube containing cadmium. The red line proved itself to be single and narrow in a high degree, and the green line was not far behind.
But although in Michelson’s hands the apparatus has done excellent spectroscopic work, it is not without its weak points. A good deal of labour is required to interpret the visibility curves, and in some cases the indications are actually ambiguous. For instance, it is usually impossible to tell on which side of the principal component a feebler companion lies. It would seem that for spectroscopic purposes this apparatus must yield to that of Fabry and Pérot, in which multiple reflections are utilized; this is a spectroscope in the literal sense, inasmuch as the constitution of a spectrum line is seen by simple inspection.
(R.)
1The word “interference” as formed, on the false analogy of such words as “difference,” from “to interfere,” which originally was applied to a horse striking (Lat.ferire) one foot or leg against the other.
1The word “interference” as formed, on the false analogy of such words as “difference,” from “to interfere,” which originally was applied to a horse striking (Lat.ferire) one foot or leg against the other.
INTERIM,originally a Latin word for “in the meantime.” The word was hence applied to certain edicts and decrees passed by the emperor and the diets during the reformation in Germany with the object oftemporarilysettling a controversy. These “interims” regulated points of religious and ecclesiastical difference until they could be decided by a general council. The best example of such amodus vivendiis the Augsburg Interim of 1548, drawn up by Michael Helding, Julius von Pflug and John Agricola (a medievalist, an Erasmian, and a conservative Lutheran) at the bidding of Charles V., and accepted by the diet. It was an ambiguous document, teaching from the Roman Catholic side transubstantiation, the seven sacraments, adoration of the Virgin and saints, and papal headship, and from the Protestant, justification by faith, marriage of priests, the use of the cup by the laity. Maurice of Saxony was permitted to vary the interim for his dominions, and his edition was called the Leipzig Interim. An earlier interim was that of Regensburg, 1541.
INTERLACED ARCHES,the term for a scheme of decoration employed in Romanesque and Gothic architecture, where arches are thrown from alternate piers, interlacing or intersecting one another. In the former case, the first arch mould is carried alternately over and under the second, in the latter the mouldings actually intersect and stop one another. An example of the former exists in St Peter’s in the East, Oxford, and of the latter in St Joseph’s chapel, Glastonbury, and in the cathedral of Bristol.
INTERLAKEN,a Swiss town (1864 ft.) in the canton of Berne, situated on the flat plain (Bödeli) between the lakes of Brienz (E.) and of Thun (W.), and connected by steamer, as well as by railway (17½ m.) with the town of Thun. It is built on the left bank of the Aar, and grew up around the religious house of Austin Canons, founded about 1130 and suppressed in 1528. In the surviving buildings of the convent religious services (Anglican, Scottish Presbyterian and French Protestant) are now held, while the more modern castle is occupied by offices of the Cantonal Government. The fine and well-shaded avenue called theHöhewegruns through the main portion of the town, and is lined on the north side by a succession of huge hotels and the large Kursaal. Interlaken is much frequented in summer, partly because of the glorious view of the Jungfrau (13,669 ft.) which it commands to the south, and partly because it is the best starting-point for many excursions, as to Schynige Platte, Lauterbrunnen and Grindelwald. The lines serving these places all start from the eastern railway station (that from Thun reaches the western or main railway station), whence steamers depart for the Giessbach Falls, Brienz and Meiringen, on the way to Lucerne or to the Grimsel Pass. In 1900 the population of Interlaken was 2962 (mainly Protestant and German-speaking). Opposite Interlaken, and on the right bank of the Aar is Unterseen (in 1900, 2607 inhabitants), which was built in 1280 by Berthold von Eschenbach.
SeeFontes rerum Bernensium(original documents up to 1366) (8 vols., Berne, 1883-1903);Die Regesten des Klosters zu Interlaken(Coire, 1849); E. Tatarinoff,Die Entwickelung der Probstei Interlaken im XIII. Jahrhundert(Schaffhausen, 1892).
SeeFontes rerum Bernensium(original documents up to 1366) (8 vols., Berne, 1883-1903);Die Regesten des Klosters zu Interlaken(Coire, 1849); E. Tatarinoff,Die Entwickelung der Probstei Interlaken im XIII. Jahrhundert(Schaffhausen, 1892).
(W. A. B. C.)
INTERLOPER,one who interferes in affairs in which he has no concern. This word, with the verbal form “to interlope,” first appears at the end of the 16th and beginning of the 17th century in connexion with the interference of unauthorized persons in the trading monopoly of the Russia Company and later of the East India Company. TheNew English Dictionaryquotes from H. Lane (1590),Hakluyt’s Voyages, “From those parts the Muscovites were furnished out of Dutchland by enterlopers with all arts and artificers and had few or none by us,” and also from theMinutes of the Court of the East India Company, 22nd of February 1615, “to examine all suspected personnes that intend interlopinge into the East Indies or Muscovy.” Edward Phillips (New World of Words, 1658) defines interlopers at common law as those “that without legal authority intercept the trade of a company, as it were Interleapers.” The word appears to be of English origin, for the Dutchenterlooper, smuggler, often given as the source, was taken from English, as was the Frenchinterlope. The word is a compound ofinter, between, andlope, a dialectal variant of “leap.” A common word for a vagrant, or “straggler,” as it is defined, was till 1580 “landloper,” and the combination of “straggler” and “interloper” is found inHorsey’s Travels(Hakluyt Soc.), 1603-1627, “all interlopers and straglyng Englishmene lyving in that country.”
INTERNATIONAL, THE.The International Working Men’s Association, commonly called “The International,” was formed at London in 1864. It was a society of working men of all nations, somewhat like a cosmopolitan trades union, butbearing a still closer resemblance to an international social science association for discussing and furthering the rights of labour. The occasion of its formation was the visit of some French workmen to the London Exhibition of 1862. In the course of their visit the labour question was discussed, and a desire for the further interchange of ideas expressed. Nothing decisive was done till 1864, when a great public meeting of working men of all nations was held at St Martin’s Hall, London, and a provisional committee was appointed to draft the constitution of the new association.
The first four congresses of the International, held at Geneva (September 1866), Lausanne (1867), Brussels (1868), and Basel (1869), marked the rapid development of the association. It gained its first triumph in the effectual support of the bronze-workers at Paris during their lock-out in 1867; and it repeatedly aided the English unionists by preventing the importation of cheap labour from the continent. It soon spread as far east as Poland and Hungary, and it had affiliated societies with journals devoted to its cause in every country of western Europe.
It was supposed to be concerned in all the revolutionary movements and agitations of Europe, gaining notoriety as the rallying point of social overthrow and ruin. Its prestige, however, was always based more on the vast possibilities of the cause it represented than on its actual power. Its organization was loose, its financial resources insignificant; the continental unionists joined it more in the hope of borrowing than of contributing support. At the successive congresses its socialistic tendencies became more and more pronounced; it declared its opposition to private property not only in railways but in mines and the soil, holding that these should revert to the community. Even the principle of inheritance was saved only by a narrow majority. In 1869 M. Bakunin, the Russian socialist or nihilist, with his party joined the association, and at once asserted his character as the “apostle of universal destruction.”
The relation of the association to the communal rising at Paris in the spring of 1871 has been the subject of much dispute. It is now agreed that the International as such had no part either in originating or conducting it; some of its French members joined it, but only on their individual responsibility. Its complicity after the event is equally clear. After the fall of the commune the general council of London, Karl Marx included, issued a long and trenchant manifesto, approving its action and extolling the “glorious vanquished.” From this point the decline and fall of the association is to be dated. The English unionists, intent on more practical concerns at home, never took a deep interest in its proceedings; the German socialists were hindered by law from corporate action; America was too remote. But it found its worst enemies amongst its own friends; the views of Marx and his school were too moderate for the universally subversive principles of M. Bakunin and the radical Swiss federation of the Jura. It came to a rupture at the congress of 1872, held at the Hague, when Bakunin, being outvoted and “excommunicated” by the Marx party, formed a rival International, which found its chief support in Spain and Italy. Wearied of its European contentions and desirous to form a basis of operation in America, the Marx International now transferred the seat of its general council to New York; but it survived just long enough to hold another congress at Geneva in 1874, and then quietly expired.
The party of destruction styling themselves “autonomists” had a bloodier history. The programme of this party was to overturn all existing institutions, with the view to reconstructing them on some vague communal basis such as had been tried at Paris in 1871. It endeavoured to realize this in the great communal risings in southern Spain in 1873, when its adherents set up their peculiar form of government at Barcelona, Seville, Cadiz and Cartagena—at the last-mentioned place also seizing part of the ironclad fleet of Spain. As at Paris, they failed in leadership and organization, and were suppressed, though not without difficulty, by the national troops. The “autonomists” lingered on till 1879. The collapse was complete of an association which once extended from Hungary to San Francisco, and alarmed the minds of men with visions of universal ruin.
See Villetard,Histoire de l’Internationale(Paris, 1871); Testut,L’Internationale(Paris, 1871); Onslow Yorke,Secret History of the International(London, 1871); J. Rae,Contemporary Socialism; also the articlesMarxandSocialism.
See Villetard,Histoire de l’Internationale(Paris, 1871); Testut,L’Internationale(Paris, 1871); Onslow Yorke,Secret History of the International(London, 1871); J. Rae,Contemporary Socialism; also the articlesMarxandSocialism.
INTERNATIONAL LAW,the general term for the law governing the relations and intercourse of states with one another. The parties in its application are states (seeState) and not nations, so that the word “international” does not accurately limit the scope of the subject. Nor do authors always confine themselves to its proper limitation. Thus the rules relating to nationality and naturalization, extradition, patents, trade marks, &c., which affect states on the one side and foreign persons on the other, are generally included among the subject-matter of International Law. There is a special branch of International Law known as Private International Law (seeInternational Law, Private) which deals exclusively with the relations of persons belonging to different states, in which states as such are not parties.
The term “international” was first used by Bentham. His explanation of the new term was as follows:—
“The wordinternational, it must be acknowledged, is a new one; though, it is hoped, sufficiently analogous and intelligible. It is calculated to express, in a more significant way, the branch of law which goes commonly under the name of “law of nations,” an appellation so uncharacteristic that, were it not for the force of custom, it would seem rather to refer to internal jurisprudence. The chancellor d’Aguesseau has already made, I find, a similar remark; he says that what is commonly calleddroit des gensought rather to be termeddroit entre les gens. There remain then the mutual transactions between sovereigns as such, for the subject of that branch of jurisprudence which may be properly and exclusively termed international.”1
“The wordinternational, it must be acknowledged, is a new one; though, it is hoped, sufficiently analogous and intelligible. It is calculated to express, in a more significant way, the branch of law which goes commonly under the name of “law of nations,” an appellation so uncharacteristic that, were it not for the force of custom, it would seem rather to refer to internal jurisprudence. The chancellor d’Aguesseau has already made, I find, a similar remark; he says that what is commonly calleddroit des gensought rather to be termeddroit entre les gens. There remain then the mutual transactions between sovereigns as such, for the subject of that branch of jurisprudence which may be properly and exclusively termed international.”1
There has been much controversy as to the aptness of the use of the word “law” in this connexion. “International law,” said the 3rd marquess of Salisbury in a speech on the establishment of a Court of International Arbitration, “has no existence in the sense in which the term ‘law’ is usually understood. It depends generally upon the prejudices of writers of text-books. It can be enforced by no tribunal, and therefore to apply to it the phrase ‘law’ is to some extent misleading.”2This has been more or less the view not only of most British statesmen but also of many practical English jurists. It found one of its most emphatic exponents in Lord Chief-Justice Coleridge. “Strictly speaking,” he observed in his judgment on the Franconia case,3“international law is an inexact expression, and it is apt to mislead, if its inexactness is not kept in mind. Law implies a lawgiver and a tribunal capable of enforcing it and coercing its transgressors, but there is no common lawgiver to sovereign states, and no tribunal has the power to bind them by decrees or coerce them if they transgress. The law of nations is that collection of usages which civilized states have agreed to observe in their dealings with one another. What these usages are, whether a particular one has or has not been agreed to, must be matter of evidence. Treaties and acts of states are but evidence of the agreement of nations, and do not, in England at least,per sebind the tribunals. Neither certainly does a consensus of jurists, but it is evidence of the agreement of nations on international points, and on such points, when they arise, the English courts give effect as part of English law to such agreement.”
In opposition to this view may be cited the more recent one expressed by Lord Russell of Killowen, who challenged Lord Coleridge’s view as “based on too narrow a definition of law, a definition which relies too much on force as the governing idea.” “If,” he added, “the development of law is historically considered it will be found to exclude that body of customary law which in early stages of society precedes law. As government becomes more frankly democratic, laws bear less and less the character of commands imposed by a coercive authority, and acquire more and more the character of customary law foundedon consent.... I claim that the aggregate of the rules to which nations have agreed to conform in their conduct towards one another are properly to be designated International Law.”4This recalls Blackstone’s definition: “The law of nations is a system of rules, deducible by natural reason, and established by universal consent among the civilized inhabitants of the world, in order to decide all disputes, to regulate all ceremonies and civilities, and to ensure the observance of justice and good faith in that intercourse which must frequently occur between two or more independent states, and the individuals belonging to each.”5The current English narrower view owes its origin chiefly to the influence of John Austin, and the current broader one to that of Sir Henry Maine.6The increasing popularity of references to international arbitration (seeArbitration, International), the adoption of a large number of special treaties making such references compulsory in certain cases, the establishment of and increasing recourse to the court for the decision of difficulties between states created by The Hague “Convention for the pacific settlement of disputes between States” of 1899 (seePeace), the adoption of fixed rules of law in the international conventions in 1899, 1907 and 1909 dealing with many of the most controversial questions of international usage, have so transformed the subject that if, as Lord Coleridge said, law implies a lawgiver and a tribunal capable of enforcing it, these conditions are now at any rate partly fulfilled. We shall see below to what extent it may be necessary to regard power of enforcement against transgressors as requisite to give international law the character of law properly so-called.
Sanctions.—The subject of the enforcement of International Law, or its “sanctions,” has given rise to much controversy. The word “sanction” is derived from the Lat.sanctio, which in turn is derived fromsancire, to consecrate. In its original sensesanctiomeans consecration. From this followed the sense of religious obligation. Thussancire legemis used by Roman writers as meaning that observance was made obligatory, but without reference to the idea of there being a remedy or penalty for non-observance. With the development of an organized judicial system the religious or moral obligation was displaced by the growth of remedial procedure. Cicero observes of some legal restrictions,hoc non sancitur lege civili(this is not consecrated by the civil law,i.e.with penalties). A collateral sense of the word grew up which meant ratification, as where Cicero speaks ofsancire acta Caesarisor ofsancire foedus.
Bentham, who worked out the theory of legal sanctions as applied to modern law, describes them as equivalent to pleasures and pains derived from four different sources. These are physical, political, moral and religious. The first three belong to experience in the present life, the fourth to that in the present life or hereafter.7
Austin’s analysis of this vague subdivision led him to a more precise determination of the relationship of sanctions to law, viz. that a law properly so-called is a command and its sanction is the power to enforce obedience to it. Stated briefly, any other kind of law according to Austin is not positive law but merely called so by analogy. Applying this test to International Law he concludes that the law obtaining between nations is not positive law; for every positive law is set by a given sovereign to a person or persons in a state of subjection to its author. The law obtaining between nations is only law set by general opinion, with duties which are only enforced by moral sanction; by fear on the part of nations, or by fear on the part of a sovereign, of provoking general hostility, and incurring its probable evils, in case they should violate maxims generally respected.8
Sir H. Maine’s somewhat indirect answer to Austin may now be taken as the view held at least by British theoretical writers. “Austin,” he said, “has shown, though not without some straining of language, that the sanction is found everywhere, in positive law, civil and criminal. This is, in fact, the great feat which he performed, but some of his disciples seem to me to draw the inference from his language that men always obey rules from fear of punishment. As a matter of fact this is quite untrue, for the largest number of rules which men obey are obeyed unconsciously, from a mere habit of mind. Men do sometimes obey rules for fear of the punishment which will be inflicted if they are violated, but, compared with the mass of men in each community, this class is but small; probably it is substantially confined to what are called the criminal classes, and for one man who refrains from stealing or murdering because he fears the penalty there must be hundreds of thousands who refrain without a thought on the subject.”9
The view, however, that a law is not devoid of binding character because there is no authority to enforce its observance hardly requires justification at the present day. The fact that any well-established international usage is observed, and that states invariably endeavour to answer any reproach of departing from such usage by explanations showing that the incriminated act is justified by recognized rules of International Law, is evidence of its binding character. As the late Professor Rivier, one of the leading authorities on Roman Law, as well as an international jurist of eminence, has expressed it: “The law of nations is positive law because states wish it to be so. They recognize its compulsory character and proclaim it. As they are their own legislators and make their common laws by express or tacit consent, they attest explicitly and implicitly their conviction that its principles are binding upon them, as judicial principles, as law. Innumerable public acts, affirmations, declarations and conventions are there to prove it. On the other hand, never in any published official act of the present age, verbal or written, has a state dared to declare that it did not consider itself bound by the law of nations and its principles.”10States, as Professor Rivier says, have again and again solemnly declared their determination to abide by the principles of International Law. Witness the Declaration of Aix-la-Chapelle of November 15, 1818, in which the representatives of five powers, Austria, France, Great Britain, Russia and Prussia, solemnly stated that “the sovereigns in forming this august union have regarded as its fundamental basis their unchangeable resolution never to depart, either amongst themselves or in their relations with other states, from the strictest observance of the principles of the law of nations, principles which, in their application to a permanent state of peace, can alone effectively guarantee the independence of each government and the stability of the general association.” In the negotiations for the Treaty of London concerning the Black Sea (March 13, 1871), at which seven powers were represented, Austria-Hungary, France, Germany, Great Britain, Italy, Russia and Turkey, a resolution on the sanctity of treaties was annexed to the first protocol, stating that the plenipotentiaries recognize that it is an essential principle of the law of nations that “no power can liberate itselffrom the engagements of a treaty, nor modify the stipulations thereof, unless with the consent of the contracting powers by means of an amicable arrangement.” Even in 1908, when Austria-Hungary proceeded to the annexation of Bosnia-Herzegovina without obtaining the prior assent of the high contracting powers, who under the treaty of Berlin of 1878 had granted her temporary occupation of the annexed provinces, the protests of the powers concerned were answered by Austria-Hungary declaring that she had done nothing contrary to the law of nations or affecting the sanctity of treaties, because the powers had given their tacit consent to the practical transformation of her temporary into a permanent occupation.
The public opinion of the civilized world, in fact, plays in an ever-increasing degree the part of a sanctioning authority. With the growth of international intercourse and international interdependence the danger of isolation or of discredit or even of “boycotting” becomes a matter of increasing importance in the conduct of states. The national press and periodical literature, with exceptions no doubt, are among the chief factors in the development of this public opinion, but it is by no means dependent upon them. Personal intercourse among citizens of the same country, and between statesmen, politicians and citizens of different countries has a still greater effect in the creation of the mental attitude of nations towards each other. This exposes any departure from recognized usage or any disregard for international obligations to such reprobation throughout the whole world, that, far from taking advantage of the absence of any coercive method of enforcing obedience to the principles of international law, states compete with each other in asserting their strict fidelity to such principles. And now successive diplomatic conferences have codified many of the chief branches of international usage, thus diminishing the possible cases in which states can take advantage of the uncertainty of the law and, by quibbling over its interpretation, escape from its obligations.
Sources and Foundations.—It is usual, following Wheaton’s classification,11to enumerate the sources of International Law in the following groups: text-writers of authority as witnesses of usage; treaties of peace, alliance and commerce; ordinances of particular states, prescribing rules for the conduct of their commissioned cruisers and prize tribunals; adjudications of international tribunals; written opinions of official jurists given confidentially to their own government; history of wars, negotiations, treaties and other transactions relating to the public intercourse of nations. It is in these different classes of opinions and precedents that writers have been in the habit of searching for those arguments and analogies on which have been built up the system and principles called International Law.
Wheaton, it is seen, regarded text-writers as witnesses of the usage of nations. He explains his meaning as follows: “Without wishing to exaggerate the importance of these writers, or to substitute in any case their authority for the principles of reason, it may be affirmed that they are generally impartial in their judgment. They are witnesses of the sentiments and usages of civilized nations, and the weight of their testimony increases every time that their authority is invoked by statesmen, and every year that passes without the rules laid down in their works being impugned by the avowal of contrary principles.” This distinguished writer’s quasi-explanation of the sources of International Law is extremely vague. He masses together cause and effect, private and public opinions, usage and exceptions. Professor Oppenheim has endeavoured to give a more scientific explanation of the growth and development of International Law, and objects to calling sources of International Law what are mere factors influencing its growth:—
“... Custom and treaties,” he observes, “are the two exclusive sources of the Law of Nations. When writers on International Law frequently enumerate other sources besides custom and treaties they confound the term ‘source’ with that of ‘cause’12by calling sources of International Law such factors as influence the gradual growth of new rules of International Law without, however, being the historical facts out of which these rules receive their legal force. Important factors of this kind are: Opinions of famous writers on International Law, decisions of prize courts, arbitral awards, instructions issued by the different states for the guidance of their diplomatic and other organs, state papers concerning foreign politics, certain municipal laws, decisions of municipal courts. All these and other factors may influence the growth of International Law either by creating usages which gradually turn into custom, or by inducing the members of the Family of Nations to conclude such treaties as stipulate legal rules for future international conduct.“A factor of the special kind which also influences the growth of International Law is the so-called comity (Comitas gentium, Convenance et courtoisie internationale, Staatengunst). In their intercourse with one another states do observe not only legally binding rules and such rules as have the character of usages, but also rules of politeness, convenience and goodwill. Such rules of international conduct are no rules of law, but of comity. The Comity of Nations is certainly not a source of International Law, as it is distinctly the contrast to the Law of Nations. But there can be no doubt that many a rule which formerly was a rule of International Comity only is nowadays a rule of International Law. And it is certainly to be expected that this development will go on in future also, and that thereby many a rule of present International Comity will in future become one of International Law.”13
“... Custom and treaties,” he observes, “are the two exclusive sources of the Law of Nations. When writers on International Law frequently enumerate other sources besides custom and treaties they confound the term ‘source’ with that of ‘cause’12by calling sources of International Law such factors as influence the gradual growth of new rules of International Law without, however, being the historical facts out of which these rules receive their legal force. Important factors of this kind are: Opinions of famous writers on International Law, decisions of prize courts, arbitral awards, instructions issued by the different states for the guidance of their diplomatic and other organs, state papers concerning foreign politics, certain municipal laws, decisions of municipal courts. All these and other factors may influence the growth of International Law either by creating usages which gradually turn into custom, or by inducing the members of the Family of Nations to conclude such treaties as stipulate legal rules for future international conduct.
“A factor of the special kind which also influences the growth of International Law is the so-called comity (Comitas gentium, Convenance et courtoisie internationale, Staatengunst). In their intercourse with one another states do observe not only legally binding rules and such rules as have the character of usages, but also rules of politeness, convenience and goodwill. Such rules of international conduct are no rules of law, but of comity. The Comity of Nations is certainly not a source of International Law, as it is distinctly the contrast to the Law of Nations. But there can be no doubt that many a rule which formerly was a rule of International Comity only is nowadays a rule of International Law. And it is certainly to be expected that this development will go on in future also, and that thereby many a rule of present International Comity will in future become one of International Law.”13
We prefer to regard International Law as deriving the rules composing it from practically the same sources as domestic law, and to attribute to text-writers more or less the same value in its development as in that of the privatePrecedents.law of nations. The same primary rules of conduct are appealed to between states as between individuals, and precedents play exactly the same part wherever human actions are concerned. In both cases what has been done before commends itself when the responsibility of taking steps pledging the future is concerned. Statesmen on whom great responsibility impends, on whom the conduct of momentous negotiations has devolved, and who will have to render an account of their work to the sovereign or nation they represent, preserve an argument in their own favour in departing as little as possible from any course taken in previous similar circumstances. Precedents, moreover, are arguments for acceptance by their adversaries or counter-negotiators. In fact, in diplomacy even more than in matters of domestic government precedents play a dominant part in the growth of usage. These precedents are often in themselves originally local usages, such as grew up in the intercourse of the ItalianItalian influence.communities. Italy, in fact, served as a laboratory for early diplomatists and writers. It was in the intercourse of these active and ambitious states that grew up the very notion of a foreign diplomacy and the necessity of rules of conduct in this miniature Europe, with its perpetual antagonisms and jealousies, its balance of power, its idea of a state distinct from a nation and of a community ofstates elbowing each other in their daily contact. It was there that grew up the institution of passports, the distinction between armed forces and civilians, international comity, and in fact the very notion that states have an interest in the observance of law and order among them. In the same way the active commercial intercourse in the Mediterranean led, in the common interest, to the development of rules of the sea in time of peace, and later to others in time of war.
In the north of Europe, again, out of the active commercial intercourse among the Baltic and North Sea communities grew rules of the sea in the same common interest. It was the Thirty Years’ War, with its revolting cruelty,Thirty Years’ War.which brought out the contrast between the more humane practice of war as an art in Italy and the mere bludgeonry which prevailed in the brutal struggle which disgraced the first half of the 17th century. The brutality of the struggle turned thinkers’ attention to the need of formulating rules for the protection in time of war of non-combatants and the innocent subjects of absolute sovereigns, the treatment of the sick and wounded, the prohibition of wanton pillage and the other horrors which shocked the awakening conscience of northern Europe. It was the starting-point of the age of text-books.
The first effective work, the one which was the first to influence sovereigns and statesmen, was Grotius’sDe jure belli ac pacis(Paris, 1625), which practically exhausted the theoretical arguments in favour of the new subject. NobodyGrotius.Pufendorf.has in fact since brought to light any new conception of the foundations of international law. An exhaustive and masterly treatise having been published, no further subsequent treatise was necessary to show what all men were beginning to feel. He sublimated the feelings of his age, and having arrived at the pure substance, the work of proving the need of his subject was disposed of for all time. Pufendorf (1632-1697), who, in the sequence of effective text-writers, succeeded Grotius, endeavoured to base international law on an ethical basis accepted by all peoples without necessity for a common creed or standard of morals, but it is doubtful, whatever may have been the extent to which he stimulated the study of jurisprudence, whether he did much in advancing the practical development of the law of nations. His bookDe jure naturae et gentium(1672), as its name indicates, based international law on what he called the law of nature, a subject which has much exercised the minds of jurists searching for an ethical basis for existing law.
The scientific mind of Leibnitz (1646-1716) revolted against this theoretical and doctrinaire tendency of Pufendorf and other writers, who were following with feeble tread in the giant footsteps of Grotius. He saw that the practiceLeibnitz.of nations was taking a course dictated by the current moral standards of civilized society, and that the philosophizing of the text-book writers was leading them away from that actual practice which they should use as data for their conclusions. Natural science, moreover, had taught him the risk of theorizing on imperfect data, and while writing a history of Brunswick it occurred to him that treaties and diplomatic documents generally were the substances and tests of the publicist’s laboratory. Hiscodex juris gentium diplomaticus(1693-1700) gave a more precise direction to speculations on the subject.
The next great writer of authority united all the qualities of a practical lawyer and jurist. This was Bynkershoek (1673-1743). He was the first writer on international law who dealt with public maritime law as a matterBynkershoek.demanding special treatment and involving a set of principles not called into action in territorial warfare. A magistrate administering the law in a great commercial country, whose interests were on or across the high seas rather than within the narrow European limits of Holland, Bynkershoek, like Leibnitz, searched for his data in the actual practice of nations in their intercourse with one another. He applied his clear legally trained mind to deriving principles from practice instead of endeavouring to build up a practice on abstract principles. It was he who first generalized the different isolated usages which had grown up at different spots in northern Europe in the interest of maritime defence, and evolved from practice the principle that dominion seawards was limited to the extent to which it was possible to enforce it (cannon-shot range), a principle which not only created the legal institution of territorial waters, but has since been imported into other branches of International Law, and has indirectly influenced the suppression of fictitious blockades and more recently of fictitious occupations of territory.
A contemporary of Bynkershoek was Christian de Wolff (1679-1754), a philosopher, mathematician, theologian, lawyer and disciple of Leibnitz. Wolff’s great work on theInstitutions of the Law of Nature and Nationsis a learnedC. de Wolff.and accurate treatise drawn from all the well-known sources of knowledge, and, just as Grotius based his demonstrations on the then imperfect knowledge of public events of his time, Wolff based his on the more accurate sources of information which had grown up under the influence of Leibnitz, and created a connected system out of the scattered fragments available. But his book was written in Latin at a period when scholarship had declined, and its influence was only felt after Vattel (1714-1767) wrote hisDroit des gens, ou principes de la loi naturelle appliquées à la conduite et aux affaires des nations et des souverains(1758). His book had all the charm, although Vattel was aVattel.Neufchatelois, of the French writers of his time, and he it was who popularized the study of International Law. His book was based chiefly on the work of Wolff, but in it he gave what was best amongst his predecessors without attempting to add anything original of his own. It became the handbook of statesmen and jurists, and has never ceased to be quoted by them down to the present day.
But the opinions of jurists in International Law can have little more than the value of criticism and co-ordination. They have seldom served to make law, though they have the weight of all statements made by those who have made a special study of any branch of law, as to what they had gathered to be the existing practice at the time when they wrote, or as to the trend which they showed that practice might be taking. Great lawyers and writers like those we have mentioned, and such as Lord Mansfield, Sir William Scott, Chief-Justice Marshall and others, have done the work of classifying facts, deducing conclusions from them and connecting rules with psychological and ethical motives, and have thus sent a current of higher intelligence through the subject which has raised it to its present methodical form. Still International Law remained a wide field for controversy. Authors were agreed on general principles, but when these general principles were applied in practice, the shortcomings of unwritten usage often caused as much difficulty as that which the appeal to principles was intended to overcome.
What may be called the first enactment of rules of International Law was the Declaration of Paris of 1856, but the great work of codification, or rather of reducing into writing the rules which had been floating as an unwritten lawHague and London Conferences.in the conscience of Europe, was undertaken by the Hague Conferences, which may be said to be and to have created an entirely new factor in the domain of International Law. Two of the conventions adopted in 1899 completed work which had already been commenced long before, viz. those on the usages of war and on the adaptation of the Geneva Convention to naval war. The third established methods for the pacific settlement of international difficulties, including the formation of the Hague Court of Arbitration. Recourse to the latter was purely optional, but the other two conventions have been absorbed into the national law of the ratifying countries, and thus have also the domestic sanction states give to their own laws. The work of the Conference of 1907 was of a much wider and more exhaustive character than that of 1899. It comprised, besides revised conventions on the matters dealt with in 1899, new Conventions on the following subjects: Opening of hostilities; Position in naval war of enemy’s merchant ships at beginning of hostilities; Conversion of merchant vessels into warships; Rights and duties of neutral states in naval war; The laying of automatic submarine contact mines; Thebombardment of undefended places by naval forces; Treatment of fishing vessels, postal correspondence and capture generally in maritime war; and Recovery by force of contract debts. It also adopted a convention for the creation of an International Prize Court of Appeal, which led to the calling of a fresh Conference on Prize Law. This conference sat in London from December 4, 1908, to February 26, 1909, and was confined to representatives of the following countries: Great Britain, France, Germany, United States of America, Italy, Austria-Hungary, Russia, Japan, Holland and Spain. It adopted a series of rules on naval warfare relating to Blockade in time of war; Contraband of war; Unneutral service; Destruction of neutral prizes; Transfer to neutral flag; Enemy character; Convoy; and Resistance to search and Compensation.
The revolution effected in the relations of states by the Hague and London Conferences, however, is not confined to the reduction into writing of more or less vague usages nor to the elaboration of details which no usage can possibly determine. Until a machinery was provided for the reform of the law it was futile to speculate on the advantages or disadvantages of any rule admitted by the majority of civilized nations. The territorial waters 3 m. limit, for instance, had its origin in the distance seawards of cannon-range in a past period. Its almost universal recognition only came long after the range of coast-guns had far exceeded this distance. This superannuated rule has now no legal basis at all except the so-called “common consent of nations,” a boon no doubt which outweighs any consideration of absolute fitness still unrecognized, but of which the learned Barbeyrac truly said,14“Ce commun consentement des peuples que l’on suppose avoir force de loi est une chose qu’on ne prouvera jamais.” The institution of the Hague Conferences has now provided a method of obtaining the consent of nations, not only to existing rules, but to their reform and to the introduction of new rules. It is now an understanding among the states of the world, that these conferences shall be held periodically. It is, of course, possible for one great state to hold aloof and thus wreck the chances of universal agreement, but even then we have the power of the majority as against that of the minority. A case actually arose in a recent war between non-signatories of the declaration of Paris of 1856. Neither the United States nor Spain was a party to that declaration, yet neither ventured to disregard it.
The chief source of International Law will, therefore, in all probability for the future be that “Parliament of mankind,” the Hague Conferences. The Hague Court and its adjunct in time of war, the proposed International Prize Court of Appeal, will form the Judicature applying and construing the enactments of the Conferences acting as a sort of international Legislature.
Fundamental Principles.—Underlying the details of both the new International Legislature and the new International Judicature are certain principles which may some day have to be officially defined. These principles haveStandard of right conduct.necessarily fluctuated with the standard of morals of each period. With the contemporary development of the public conscience, they are undergoing changes and a betterment which it is not desirable to check by yet nailing them up as immutable articles of faith. Till quite recently it was usual to speak of the common standard of right conduct prevailing throughout the Christian world, a standard to which responsible statesmen tried to adjust their direction of the affairs of state. The admission of Japan into the councils of the great powers has introduced a non-Christian element whose standard of conduct was not identical with nor based upon Christian morals. Turkey, though admitted in 1856 to European Councils, remained rather the occasion of their deliberations than a deliberating party. Her new position as a constitutional state, with a code of morals at any rate in some essentials distinct from that of Christian peoples, will add a further new non-Christian element into the moral foundations of international conduct. The influence of western Europe, however, in both Japan and Turkey, has hitherto in all external development been paramount. Japan, after examining all the existing systems, has even adopted the best she found in Western morals, and in her schools inculcates Christian ethics as a subjectper sewithout reference to divine revelation or authority. Turkey too has the advantage of possessing a code of morals which produces so high a standard of right conduct in private life that very little in the way of moral lessons will have to be learned by the Ottomans from Western civilization. As regards practice, it is unreasonable to expect that the high estimate of the moral standard of west European civilization, which is cherished by those who profess its principles, should be accepted by other peoples with unqualified assent. Are not the nations of western Europe still vaguely influenced by the instincts of their conquering ancestors, and by the traditions of—
“... the good old rule,... The simple plan,That they should take who have the powerAnd they should keep who can”?
“... the good old rule,
... The simple plan,
That they should take who have the power
And they should keep who can”?
There is nothing essentially different between many recent wars and military enterprises undertaken by Western nations against heathen peoples, and wars and conquering enterprises undertaken by the Northmen of a thousand years ago. In hisNorthern AntiquitiesMallet15describes the primitive feeling of the Northmen in the following passages:—