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    "source_key": "britannica_1926",
    "source_title": "Encyclopaedia Britannica (1926)",
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    "chunk_id": "1926:catalysts:041be45de4aa",
    "title": "CATALYSTS",
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    "verified_text": "the term catalytic agent (gr. to break up) was introduced by berzelius (jahresbericht, ttibingen, 15,1836) to include those substances which by their presence accelerate the rate of reactions proceeding with a de- crease in free energy towards equilibrium without undergoing any change in themselves. in reversible systems catalysts thus neces- sarily accelerate the rates both of the forward and reverse reactions. many cases of supposed altcration in the conditions of equilib- rium for the catalysed and noncatalysed reaction have been noted, but closer examination has shown in many cases, either that true equilibrium was not attained or that the catalyst was 549 added in quantity sufficient to affect the active mass of one or more of the reactants. although taking part in the reaction a catalyst, being constantly reformed, should be able to effect the conversion of an unlimited amount of reactant. in practice, this is not realised, as loss of the active catalyst occurs. this loss may occur (2) through side reactions, unconnected with the main reaction, as in the gradual reduction of sulphuric acid in etherification processes; (6) through the formation of inactive compounds with impurities present in the reactants, as in the formation of nickel sulphide from sulphur compounds present as impurity in hydrogen employed in hydrogenation processes; (c) through removal from the reacting system, either by vaporisa- tion as in the case of platinum catalysis for the formation of sulphur trioxide, or by coagulation as occurs in colloidal metal catalysts employed for hydrogenation; (d) through sintering and fusion due to overheating of the active surfaces. causes of acceleration.—acceleration of reaction rates by catalysts is due to the opening of a fresh avenue for molecular reaction in which the catalyst plays a part. if two substances a and b react and form a product c a reaction accelerated by a catalyst x two simultaneous reactions take place gy aer sc.gy) acb nsc ex catalytically accelerated reactions may be homogeneous or heterogeneous in character, the former taking place in gases and liquids, the latter at interfaces more especially at gas solid and liquid solid interfaces. in all cases it is now generally assumed that reaction proceeds through the formation of temporary com- plexes; thus the above reactions can be expressed as a sequence of changes (1) a+-b-(ab)—-c, (2) a+ b+x—(abx)—-ck--c+yx. whilst in many cases unstable intermediary complexes of the type ab, e.g., benzoyl peroxide, ester-acid compounds can be isolated at low temperatures, the ternary complex reactants- catalyst abx is usually present in subanalytical quantities and its existence frequently postulated from identification of the more stable binary compounds ax, bx, ab. all binary col- lisions between reacting molecules are not effective in producing combination, a large fraction generally undergoing collision and elastic reflection. two types of such reactions may be readily identified. in the union between gaseous atoms such as the reaction 2h— hy, before the hydrogen molecule can exist as a stable system, the energy liberated during combination has to be dissipated. in some cases such energy is liberated as radi- ation but frequently a third atom strikes the system within the life period of the unstable molecule, ca. 10-7 seconds, and effects the removal of the energy thus catalytically accelerating the union of the atoms. in this way surfaces catalyse the union of hydrogen atoms and sodium vapour the union of sodium and iodine atoms. liffect of temperature—more frequent are those reactions which are markedly temperature sensitive, the reaction velocity increasing exponentially with elevation of the temperature. sv. arrhenius (zeit. physikal. chem., july 1880) inferred that there existed in the reacting system, active or excited, and in- active or normal molecules in mass equilibrium with each other. acta! bob! only excited molecules underwent reaction on collision, their number increasing exponentially with the temperature. in simple cases the energy required for excitation or the critical energy increment e may be calculated from the velocity temperature 3 15) re 2 dt trautz in 1906 and, independently, perrin and mclewis in 1913 advanced arguments in favour of the view that the energy of activation required for the conversion of normal into excited molecules was supplied by radiation flowing into the reacting system. in a number of cases this hypothesis is not necessary, for if it be assumed that there are no active molecules in the system but only those molecules react which impinge on one coeflicient with the aid of the equation 559 another with such initial speeds that the available kinetic energy exceeds the critical energy increment, the agreement between the observed and calculated rates of reaction is excellent. con- firmation is seen in the decomposition rates of clo, no and h, (c. n. hinshelwood, jour. chem. soc., vol. 123, 1923; proc. roy. soc., vol. 106, series a, 1924; and m. bodenstein, zeit. physikal. chem., vol. 110, 1924). gas reactions.—these bimolecular gas reactions are catalysed by hot metal surfaces and the reactions there appear unimolec- ular in respect to the gas. catalytic acceleration is thus produced by converting a bimolecular reaction, with a large critical energy increment, necessary for two molecules, and thus a small velocity at low temperatures, into what is virtually a series of reactions, each with a lower critical energy increment and a greater veloc- ity, although the critical energy increment per molecule may be very similar in the two cases. whilst homogeneous gas reactions are more simple in character than reactions in liquids, or at interfaces, very few cases of true catalytic action in such systems are known. in addition to the cases of atom combination referred to above, two other reactions appear to be chiefly, if not completely, homogeneous in character. the decomposition rate of ozone is accelerated by gases such as helium, nitrogen and oxygen (grifhth and mckeown), whilst the numerous experiments of dixon and baker on the influence of traces of moisture on chemical actions lead to the conclusion that some of these reactions are undoubtedly homogeneous catalytic gas reactions, although surface phenomena on the walls of the containing vessel are frequently of predominating importance. to explain such reactions on the hypothesis of activation by collision it is necessary to assume that a molecular complex, e.g., breph20 is more readily activated on collision than a simple molecule br. evidence from a study of absorp- tion spectra of wet and dry vapours and liquids is beginning to support the view that the energy of excitation for such complexes formed with polar molecules is less than that necessary for simple molecules. liguids.—in liquids, cases of catalytic acceleration of re- actions are common, the classical examples being the catalytic activity of hydrogen and hydroxy] ions on hydrolytic changes. other ions exert marked specific effects in many cases, such as the iodide in the decomposition of hydrogen peroxide, the chloride ion in the decomposition of chloramine, organic anions in the decomposition of nitramide and the ions of polyvalent elements such as cerium, vanadium and chromium in oxidation processes. in the cases of hydrogen ion catalysis in the hydro- lysis of an ester, the reaction velocity in dilute solutions may be considered as proportional to the concentrations of the three ot brcac cster(cu, 0) when more concentrated solutions are emploved, or neutral salts are added to the solution, the reaction velocity rises more rapidly than would be anticipated from a consideration of the above equation. for other reasons we have cause to believe that electrostriction occurs in solutions and the reactants are solvated thus removing free water from the system, consequently the “thermodynamic concentration ” or “activity”? is actually greater than the apparent concentration. if the reaction velocity be assumed proportional to the con- reactants or dx r(abx) we obtain, centration of the complex abn, or ai according to the law of mass action re (a) (b) (x)_ fa fb in (abx) f(abx) where fa {/b fx are the activity coefficients of the reactants and k the mass action equilibrium constant. hence we obtain dx r (a) (b) (x) a a8 iba) f(b) (9). the dependence of the reaction velocity on the activities of the reactants and catalytic agent has been demonstrated in the catalysts inversion of sucrose, the decomposition of acetylchloramino ben- zene and the decomposition of hydrogen peroxide in the presence of hydrobromic acid, the energies of activation of catalysed re- actions in aqueous media lie between 26,000 and 10,000 calories per given molecule, values sufficiently low to permit of relatively rapid reaction at ordinary temperatures. if no catalyst be pres- ent the energies of activation for the binary complexes (a b) are proportionately higher; thus if the ester water hydrolysis in the absence of a catalytic agent required an energy of activation of some 60,000 calories, reaction would only occur at a percep- tible rate at temperatures in the neighbourhood of 700°c. the velocity of catalysed reactions in homogeneous solutions de- pends on the magnitudes both of the energy of activation and of the equilibrium constant for the system reactants complex: thus it does not necessarily follow that a reaction with a low energy of activation will proceed at a great speed. the following data from h. e. cox, jour. chem. soc., vol. 119 (1921), on the rate of addition of aniline to bromacetophenine in various sol- vents may be cited in this connection. velocity constant energy of activation 8,088 10,700 12,440 13,910 technical applications—the most important technical appli- cations uf catalytic methods are to be found in heterogeneous systems where reactions between gases such as nitrogen and hydrogen to form ammonia (see ammonta) at the surface of iron, carbon monoxide and hydrogen to form methyl alcohol and the higher alcohols at the surface of zinc oxide and sulphur dioxide and oxygen to form sulphuric anhydride at the surface of plat- inum have been developed industrially on a large scale. other large industries falling under this category include the hydro- genation of oils and fats, the oxidation of ammonia to nitric acid and the manufacture of acetic acid. heterogeneous gas reactions operate through the formation of adsorption complexes between catalyst and reactants and thus the catalytic layer at the surface of a catalytic solid is but one molecule thick. at high temperatures a reaction zone is formed on the solid surface which may be relatively thick. it is probable however that in these cases the catalyst serves to start a series of reaction chains which spreads out into the surrounding gas, at the same time thermionic emission of electrons from the hot surface occurs and it would appear that these in turn serve as exciting agents, aldsorption.—at surfaces both the reactants are generally adsorbed and the reaction velocity attains a maximum when the partial pressures of the reacting gases or the concentration of reactants in solution are so adjusted as to preserve an optimum surface concentration. such maxima have been experimentally observed in the following systems: sulphur dioxide, oxygen on the surface of platinum; ethylene, hydrogen on a nickel surface; oxalic acid, oxygen on a carbon surface. such surface reactions proceed generally at a rate which ts slow compared with gaseous diffusion but in liquid systems we frequently find a limitation of the speed of reaction imposed by the slowness of diffusion. a catalytic metal is not uniformly active over the whole of its surface, but the surfaces of the microcrystals, the edges, corners and the amorphous portions of distended crystal lattices all possess different surface energies. the fraction of the area which is capable of functioning as a catalyst is frequently minute. a good nickel catalyst has a surface efficiency of the order of r:1000, the existence of patches of varying activity ona catalyst surface has been demonstrated not only from consideration of surface energies and adsorption of various gases but also from the eflect of substances which are strongly adsorbed, t.e., poisons on the catalytic activity. it is, as shown by the experiments of vavin and husson, possible to poison a catalyst progressively, eliminating in stages the catalytic power of the surface for various reactions, the molecules adsorbed on the surface are solvent benzene chloroform . methyl alcohol . ethyl alcohol “000985 -00186 0748 -0626 cather—caucgasus, campaign in the attached by particular groups and may be considered as forming definite surface compounds similar in properties to co-ordinated compounds, although a distinction must be drawn between the properties of such substances as cuo or ni (co), and oxygen or carbon monoxide adsorbed on copper and nickel respectively. by kinetic transfer of energy and also, in certain cases, by absorption of radiation these surface compounds may be ex- cited or brought to a reactive level, thus on the adsorption of hydrogen by nickel it is found that hydrogen atoms, formed on the surface by excitation of the adsorbed molecules, may be recovered by evacuation at low pressures. promoters.—the activity of a catalytic surface may be modified by promotion, i.e., the addition of small traces of other substances termed promoters. thus palladium will promote copper, ceria iron oxide, molybdenum iron and iron will promote carbon. three distinct effects may be produced by the addition of a promoter: the total catalysed area may be increased by dispersion, the fraction catalytically active may be increased, or again specific atoms or atom groups may be augmented in activity by the juxtaposition of the foreign material. this latter appears to be similar to, if not identical with, the instability of molecules at phase boundaries first noted by faraday in the case of the efflorescence of hydrated salts. promoters are now extensively employed in industrial catalytic processes: thus zinc oxide 1s promoted with chromium oxide in the synthesis of alcohols from water gas, iron is promoted with alkali in the synthesis of ammonia from nitrogen and hydrogen, two typical high-pressure reactions. specific action.—linorganic catalysts are far less specific in character than the ferments and enzymes; nevertheless certain reactions present interesting peculiarities indicating a specific action. in homogeneous reactions abel noted that the following oxidations by hydrogen peroxide catalytically accelerated by 10dine ions and sodium molybdate were almost specific fd 28203\" +h1025,s,06\"+ 20h’ s07 agi ol so? 2 io. in heterogeneous reactions we find that the alcohols can undergo catalytic decomposition in two ways, e.g., c.h,+h.o c104 ch cho-h, the dehydrogenating reaction is more marked on metals; the dehydrating reaction on metallic oxides. it is as yet uncertain whether the difference is due to differences in structure of the adsorption compounds formed or whether the same adsorption compound can undergo different modes of decomposition when raised to different energy levels. the energies of activation of the adsorption products are, as determined from the temperature coefficients of the two reactions, at least very different. efficiency.—catalyst efficiencies are usually compared by observa- tion of the space time yields (s.t.y.) in which the yields per litre of catalyst space per hour is determined. since in general the systems are strictly reversible, complete conversion of reactants into products is not obtained when the conditions of equilibrium are attained. it follows that for slow velocities of gas flow, equilibrium is attained and the s.t.y. increases in a linear manner with the gas velocity. above a certain critical velocity equilibrium conditions are not obtained, but the s.t.y. still increases, although less rapidly, with the gas velocity. finally the s.t. y. succeeds in attaining a maxi- mum value. for industrial gas reactions it is necessary to prepare the catalyst in a form which will withstand considerable loads without crushing and present a minimum resistance to gas flow without undue diminu- tion in catalytic efficiency, inert support materials or binders being frequently incorporated to achieve this end. limits to attainment of the maximum 5s.t.y. of a catalyst may be set by the excessive cost of pumping gases or fluids at high speeds or by the difficulties associated with the maintenance of uniform temperatures in the case of strongly exothermic reactions. bibliography.—j. w. mellor, chemical statics and dynamics (1904); e. kk. rideal and h. s. taylor, catalysts tn theory and practice (1919); k. g. falk, catalytic action (1922); g. g. hender- son, catalysis in industrial chemistry (1922); p. sabatier, catalysis i” organic chemistry (1923); c. oppenheimer, die ferniente und thre wirkungen (1924). (e. k. r.) 551 cather, willa sibert (1876-— ), american author, was born at winchester, va., dec. 7 1876. after graduating at the university of nebraska in 1895, she took up newspaper work, contributing also to magazines. from 1906 to 1912 she was associate editor of afcclure’s magazine. her novel, one of ours, was awarded the pulitzer prize in 1923, and her delicate and individual work was warmly welcomed by english critics as well as by those of her own country. among her other novels are o pioneers! (1913), afy antonia (1918), a lost lady (1923) and the professor's house (1925). in 1917 she became litt.d. of nebraska university. catt, carrie chapman (18s59- ), american suffragist leader, was born at ripon, wis., jan. 9 1859. she was educated at the state college of iowa and took a special course in law, subsequently becoming high school and general superintendent of schools at mason city, iowa. she devoted her subsequent career to the cause of woman suffrage, in furtherance of which she lectured throughout the united states and in europe. she held the office of president of the national american woman suffrage assn. from 1900 to 1904 and from 1915 until the close of the campaign which resulted in the passing of the woman- suffrage amendment to the united states constitution. she organised and was president of the international woman suffrage alliance from 1904 to 1923. caucasus, campaign in the.—though both russian and turk spoke of a ‘‘ caucasus front ” and gave to their armies en- gaged on this front the designation ‘‘ caucasian,” the operations actually took place at a considerable distance from the caucasus. lhe terrain described —the main theatre of these operations may be defined as lying within the following limits: on the east, batum (on the black sea)-kars-mount ararat; on the south, lake van-mush-kharput; on the west, kemath-erzinjan- kiresiin; and on the north, the south coast of the black sea. the whole of this region is covered by the historical term ar- menia—not merely the present republic of that name, but, in the wider sense of the term, the country which was inhabited in 1914 largely by the ill-starred armenian nation. outside this main theatre of operations, a somewhat desultory warfare was carried on by detachments from the main forces up and down the western parts of persia. though some of the valleys are fertile, the area as a whole is bleak, sparsely populated and almost undeveloped. the poverty of the communications and the severity of the climate render military operations on a large scale difficult and arduous. in 1914, on the russian side, railway communication ended at sari qamish, some 4o m. southwest of kars and 15 from the fronticr; on the turkish side, 600 m. of indifferent roads and tracks separated their armies operating in the erzerum area from the nearest railhead at angora or ulu qishla, on the bagh- dad railway northwest of adana. thus the advantage in land communications lay, at the outset, very decidedly with the rus- sians, who had also, except for a short period after the outbreak of war, command of the black sea. on neither side, however, could the communications be considered in any way adequate for operations on the grand scale. few commanders would welcome a campaign in such extreme conditions of climate and difficulties of movement and supply. neither army was up-to-date in its technical organisation. the higher leading and staff work in both armies was rough and ready rather than scientific, though there were a number of german staif officers with the turk and many highly educated and intel- ligent men in the russian general staff. given the character- istics of the two armies and the restrictions to manoeuvre which the terrain imposed, it was sufficiently obvious that the campaigns were likely to be marked by hard, straightforward fighting rather than any striking display of military art. only the hardiest of soldiers could have come to grips with each other at all in that waste of snow-clad hills, in the depths of winter when the cam- paign opened. it was at the end of october 1014, that turkey definitely entered the world war on the side of the central powers, and opened hostilities by naval-bombardment of russian ports in the black sea. the strategy of the central powers would have naturally \\ a i % fj = > ae ete, ~! may d m zl, hy all > yin ar a sata van iy as fae et t piers: rays? n > s fy cold v f iw . 7 i ne ’ pene hriare vem fe fant’ inh au ths, as 4 ‘nit i fa ava; sn ay we ‘y . a ee my, in yd mh hii. bs, hese an . es an avi ali os mas sae a pasos miele . fest) erzer or min tu, quilt oy, no (re lair. oa: ie fai i ne rg, ay ye stan hai ea vv mi h wy arn a 1 rs ss 44\" e — an bs . ‘ uit aer, uni a, sy hn bs). 4 . sai a ‘ i va ss te nn ns ins tas glin ie dy yale aed ay = 4 cae kha swed a ee sia wkn cst bitlis apn sllz mul 0 th ad trs wss dictated as the most useful contribution of her new ally to the common effort a diversion likely to withdraw most russian troops from the hard-pressed austrians; and liman von sanders, the chief of the german military mission in turkey, is known to have proposed a scheme for the janding of a turkish force at odessa with this object. but this scheme, even apart from doubts whether command of the black sea could be effectively secured, was, perhaps not unnaturally, viewed with disfavour by the turks, who preferred the hope of reconquest of some of the ter- ritory, notably the fortress of kars, lost to russia in previous wars. the iii. turkish army had been assembling during sept. and oct. in the neighbourhood of erzerum. it consisted of the ix. and xi. corps, the 2nd cav. div. and some mounted irregulars. during nov. the x. corps was added, bringing the fighting strength of the army up to approximately 100,000 men. all three corps were composed mainly of anatolians, the best fighting material in turkey. the turkish plan of campaign.—the plan evolved by enver, whose megalomaniac mind seems to have dreamed of campaigns rivalling those of alexander and extending even up to india, was a wide enveloping movement with kars as the objective. the xi. corps was to attack frontally toward the russian rail- head at sari qamish, while the ix. and x. corps moved north from erzerum, swept by difficult hill passes through olti, on toward kars and sari qamish. still further north, a detach- ment which had landed at trebizond was to advance on ardahan. this grandiose plan wholly ignored the absence of communica- tions and the climatic conditions. the russian attitude was, at the outset, purely defensive; their main preoccupation was on their western front, which had absorbed nearly all the avail- able forces; two of the three regular corps, stationed in the cau- casus in peace, had been sent on mobilisation to defend the western front against austria and germany. only two com- plete corps, the 1. caucasian and ii. turkestan, were at first available for the defence of the caucasus. yet the russians made the first advance, moving a force across the frontier to kepri kei on the road to erzerum. this advance was made to secure room for manoeuvre in front of the important base at sari d ki no <a (we ~ opth i, ses wie an cru gi sf sahn aly zo aus woy ieee: ae oi ae rass ~ yf: x. \" ‘ wy. ae ti stu salts snes si ef ‘ dy, omush| * y; late saigo ling, iy => sr oa re ~ caucasus, campaign in the operations on om inn we the caucasus wg us front | english miles x ey! vas hs . ss q 2 1 % 2 fd = valet 20 ra c =s sly! ei is ste pfeil a sy ae - sne a a an “i wh <u wy re ip we ise pee & 77 ad g : * 40 kilometres a a sn | 0 20 40 + 8u ; a : er pill ae oe railways fis il ie an s39 ; pee : si d : peas ae * z a > ‘ y md” a oe g by = ; {tn ay asa : f y f. si ye me i a y “ily, hi s; he fb, 2 aa aye ars as od nes | pf an z, : arts ers y 0 iy : iz b ~~ < # ae a = i ey, vv = on a 5 pi ~~ aii ne = g== dy zh a xe tn sis oy ui dn, aa itty cs soe cay, atsc ts pis f) a bhiye ar «s 0 i us oe a, barve run nd y or ts pee aa, wig ee anne = = rect @ i qamish. the turks promptly attacked, and some fierce fighting took place between nov. 8 and 20, which ended in the with- drawal of the turks. enver now arrived from constantinople and assumed personal command of the iii. army. he insisted, against the views of his german advisers, on putting into execution the ambitious plan he had conceived. the routes by which the turning movement was made were mere mountain tracks deep in snow; the greater part of the artillery and transport had to be left behind, and the attempt seemed madness. yet such fortitude and endurance did the poorly equipped and ill-fed turkish troops display that they almost achieved the impossible. while the main russian body was engaged with the xi. corps, the ix. corps appeared, in the last days of dec., on the heights above sari qamish, and the x. corps on its left approached the railway between kars and sari qamish; the detachment from trebizond had already driven the russians out of ardahan. the russian commander’s nerve failed him at the crisis; and the situation was saved only by his chief of the staff, gen. yu- denich, a man of considerable ability and imperturbable resolu- tion. he collected forces for a counter attack, which resulted in the complete defeat and practical annihilation of the two turk- ish turning corps, worn out and disorganised by their formidable approach march; the xj. corps was then in its turn driven back. the total losses of the turkish iii. army are said to have ap- proximated to 85%. enver at once handed over the command to hawis hakki pasha and returned to constantinople. hawis hakki died shortly after, and the command was given to mahmoud kiamil. the alarm caused in russia by the turkish incursion was such that an appeal was made to great britain for a diver- sion against the turks. this led to the first suggestion for the gallipoli expedition. during the whole of rors the fighting on the caucasus front was of minor importance only. the main preoccupation of the russians jay on their western front, of the turks in gallipoli. the shattered ii. army was gradually reconstituted, and the russians raised fresh units to increase their efrenei hi: but neither side was yet in shape for a serious offensive. the detach- caucasus, campaign in the ment of turks which had in the previous winter advanced to ardahan and then been driven back to artvin attempted in april a coup de main against batum, but without success. on the other flank the russians advanced their left wing into ar- menia during may and june, occupied van and threatened bitlis. the armenian rising which assisted the russians led to bloody reprisals on their compatriots still in turkish power. in sept. 1915 the grand duke nicholas took over command of the cau- casus front, an event which was to produce a marked enlarge- ment of the russian effort in this theatre. grand dukes in iin- perial russia could still obtain reinforcements in men and matc- rial denied to ordinary commanders. nor did the character of the grand duke make it likely that he would adopt a passive role. though not a grcat strategist, he was shrewd and energetic, and, as he had already shown while in command on the western front, a most loyal and unselfish supporter of the allied cause. he found an able executive commander in gen. yudenich, already mentioned. the taking of erzerum—once again an offensive on a large scale was made in the depth of winter. the grand duke wished to anticipate the arrival of turkish reinforcements released by the british evacuation of gallipoli. this enterprise was com- pletely successful. the russian capture of erzerum was one of the finest [cats of arms of the whole war. its assault did not form part of the original plan, but the attacks up the araxes valley, begun on jan. 11 1916, so completely surprised the turk that it was decided to attempt it. the famous fortress, though many of the works and much of the armament were not modern, oc- cupies a position of great natural strength, which the turks under german supervision had improved with field works in addition to the existing forts. its capture on feb. 16 was mainly the result of a turning movement from the north, made by the ii. turkestan corps under przjevalski, the ablest of the russian corps commanders on the caucasus front, who had an intimate knowledge of erzecrum, where he had spent 15 years as military attache. the turks retired in considerable disorder with heavy losses in men and material. the next russian objective was trebizond; its capture in april considerably simplified the supply problem. meanwhile, the turkish higher command, alarmed at the fall of erzerum and continued advance of the russians, had decided on a counter- stroke. they ordered the assembly of a new army, the i., under izzet pasha, in the mush-kharput region, to attack the russian flank and rear and recapture erzerum. the plan was sound enough, had the communications allowed of a speedy concentra- tion and swift advance. but the assembly of the i. army, begun in april, was not complete in july. the grand duke became aware of the turkish intentions and anticipated their attack by a heavy blow at the iii. army, which eventually broke in complete rout. the russians occupied erzinjan in july. so heavy were the losses of the iii. army that it had subsequently to be completely reorganised. to do this divisions were formed out of army corps, regiments out of divisions, battalions out of ~ regiments. the defeat of the iii. army delayed and weakened the coun- terstroke of the ii. army, which did not take place till august, giving the russians time to transfer troops from their right wing to meet it. after some heavy fighting on the oghnat-kighi front the ii. army’s effort was definitely held. it had gained little ground at a considerable sacrifice in men. both armics then took up defensive positions for the winter. the line now ran approximately from tireboli on the black sea, west of gumush- kane to kemakh, then southeast by kighi, oghnat, mush, and bitlis to lake van. further east, on the turko-persian border and in persia, both armies had detachments to protect their flank, and fighting took place with varying fortune during 1915-6. during the winter of 1916-7 no movements took place. the turkish ii. and iii. armies (mustapha kemal and wahib pasha respectively), now combined under izzet pasha, suffered terrible privations from fack of supplies and the weather. nor were the russians in very much better case. a light line was being built from sari qamish to erzerum, but progress was very 993 slow and railhead was still some miles short of erzerum in march 1917. their command of the sea enabled them to feed their right wing from trebizond; but from erzerum and trebizond to the front, supply was dependent on horse transport over indifferent tracks, somctimes closed for days by blizzards of snow. the russians, too, suffered severely from poor rations and typhus. altempicd russo-british co-operationn—in dec. 1916 the british army in mesopotamia, under gen. maude, commenced the attacks on the turks at kut, which were eventually to lead to the capture of baghdad in march. unsuccessful efforts had previously been made to concert the operations of the british in mesopotamia and the russians in the caucasus; and now, with the approach of maude’s forces to baghdad, an opportunity for effective combination seemed to have arrived. it was agreed that the cavalry corps of baratov from persia and of chernozubov from between lakes urmia and van (both these corps, though com- posed mainly of cavalry, had a strong backing of infantry and artillery) should advance on mosul; and thus, it was hoped, in co-operation with maude, finally liquidate the mesopotamian campaign. however, it was not to be. the grand duke adopted the plan whole-heartedly, and the turk would not have been in a position to offer effective resistance. rut, first of all, the weath- er conditions and the difhculty of organising a line of supply through the mountains of the persian border caused delay; then, before the movement had well begun, the russian revolution broke out. with the recall of the grand duke toward the end of march —only to be described as an incredible blunder on the part of kerenski—the best hope of energetic action had gone. collapse of the russien army.—throughout the summer the russian army lay inactive, gradually disintegrating; by the early autumn it was sufficiently obvious that the troops would make no further forward movement, and could only be relied on to hold their positions so long as they were not attacked. yude- nich, who had succeeded the grand duke, gave up the command in august and was succeeded by przjevalski. but the end was near. in december an armistice was concluded on the caucasus front, and in jan. 1918, after the peace of brest-litovsk, the russian troops still remaining retired. the condition of the turkish armies had been too wretched to allow them up till now to take advantage of the russian collapse; but when the rus- sians finally retired, the turks were once more fired with hopes of territorial gains; and advanced on the caucasus with troops which from the military point of view would have been more profitably employed in strengthening their front in [alestine. they occupied batum on april 14 and kars on the 26th. all russian regular troops had disappeared, and their only oppo- nents were georgian and armenian bands defending their homes. the british expedition to baku.—the british generai staff, alarmed at the prospect of a caucasus under turkish control being used as a base of propaganda and even operations against india, had meanwhile organised a group of british officers and non-commissioned officers under gen. dunsterville to be sent to the caucasus to rally the local armenian and georgian popu- lations against the turk. but this force, dispatched through persia from alesopotamia, was delayed by the anarchic condi- tions which fcllowed the collapse of the russian forces in persia, and arrived too late. when it reached baku in august, things had gone too far; and after a short but gallant defence it was compelled to withdraw. but the turkish control of trans- caucasia was shortlived, for allenby’s crushing victory in pales- tine a month later spelt the loss of the war for the turks. criticisms of the campaign.—the operations of the so-called “* caucasus front ” described above thus led to no decisive re- sults on either side. in view of the poor means of communication in the theatre of operations it is difficult to see how decisive re- sults could have been expected. the lure of territorial conquest anc false strategical conceptions led the turks to attach an un- due importance to this front, which had disastrous consequences for them from a military point of view. the unnecessarily heavy losses in their best troops caused by the offensives of the iit. army at the end of 1914 and of the ii. army in 1916 caused the weakness which proved their undoing on the palestine and 554 mesopotamian fronts. had the turks been content with a de- fensive attitude on the caucasus front, british difficulties in these theatres might have been greatly increased. the purely defensive attitude which the russians took up at the outset was strategically correct; they had no other objective than the protection of their transcaucasian provinces from in- vasion; the state of the communications would obviously never allow them to penctrate far enough into asia minor to produce any decisive effect on turkey. that they advanced as far as they did—farther, perhaps, than was strategically wise—was due to the influence and energy of the grand duke. from the military point of view these campaigns are likely to be remem- bered only for one great feat of arms—the boldness and endur- ance displayed in the capture of erzerum—and as affording to soldiers one more example of the dependence of strategy on com- munications. bibliography. kaukasielli (pseud.), der kaukasus tm_welt- krieg (1916); m. p. price, war and revolution in asiatic russia (1918); peace handbooks, vol. 19, the russian lear ata etc, (1919).",
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