3rd Cav. Bde., pushed eastward in the hooe of seizing Rajgrod. There lay the left flank of the lake line, the gate to Augustovvo, and the edge of the Osowiec marshes, and it was stubbornly defended. At this moment, when the ist Landwehr, 2nd and 8oth Res. Divs. were thoroughly involved in the Lyck battle, ind the yoth Res. Div. was striving to break through at Rajgrod, Russian counter-attacks developed from the south.
The eastward driving of a wedge, originally intended, had become in fact a northward and northeastward attempt to envelop, with mere picketing of the southward-leading roads. Ludendorff, dissatisfied and anxious, had already begun to cut out parts of the converging line of battle in order to obtain forces which might even now provide a solid right face for a wedge, but these were not available on the spot when the crisis came. At first only the 4th Cav. Div., freshly detrained from Poland, could be put in front of the Russians advancing from Grajevo; and the situation was so serious that the Both Res. Div., already engaged in the flank of the defenders of Lyck, had to be counter- marched to assist the cavalry. Thus when, late on Feb. 14, the Russians finally gave up the defence of Lyck and fell back all along the line it was only their rear guard, and not the whole III. Siberian Corps, that was sacrificed. At that moment the corps had successfully transferred the weight of its defence to Rajgrod, where the German ygth Res. Div. was completely held up. Moreover, the Soth Res. Div. and 4th Cav. Div. in front ot Grajevo repulsed the counter-attack.
On this date, Feb. 14, the advance of Eichhorn and of the left of the VIII. Army had progressed day by day the troops now far ahead of supplies but living on captures till the right- angled line of Fib. 12 had become almost a semicircle. Already half of each of the ist Landwehr and 3rd Res. Divs., and the 5th Inf. Bde. which had been working with the 2nd Div., were out of the line and available for other service, besides the Konigsberg Landwehr Div. already transferred to the E. flank. In the semicircle the ygth Res. Div. and 3rd Cav. Bde. (shortly rejoined by the 8oth Res. Div. from Grajevo) were before Rajgrod, the forces which had taken Lyck (2nd and parts of the nth Landwehr Div.) at Sentken, the nth Landwehr Div. at Kleszowen, half the ist Landwehr Div. at Willkassen, half the 3rd Res. Div. and part of the roth Landwehr Div. at Raczki, and the rest of the latter before Poddubowck; while of the X. Army the XXXVIII. Res. Corps was before Suwalki, the XXXIX. Res. Corps before Tatarak and Krasnopol, and the XXI. Corps at Sejny and N. of Berzniki. In the later stages of the drive stubborn resistance had been met, for, as the parts of the Russian X. Army drew closer together and their trains became congested, more time had to be gained by rearguard fighting. But no real relief-attack had developed against Eichhorn's outer flank, either from Kovno or from Olita, and in spite of at least one favourable lake position (that of Kalwarja- Simno-Sereje) there was no counterpart on this side to the resistance offered at Lyck. Thus the eastward-running lines of retreat had been successively lost, till only those leading to Grodno, and to Lipok, Krasnyboz and Sztabin on the upper Bobr, remained open; and the whole Russian X. Army (except on its left, which held out at Rajgrod) was herded, with its guns and transport, into the great forest of Augustowo.
Thenceforward the German operations, by force of circum- stances, assumed the twofold form which the Higher Command had originally intended the tactical encirclement of the Russian X. Army and the strategic penetration of the Bobr barrier. But for the latter it was already too late. Instead of being on the river itself, the Russian forces were well in advance of it, at Stowiski, at Grajevo and at Rajgrod, preventing a coup de main, and the thaw had reduced the marshes of Osowiec to a condition in which positions for siege artillery were not to be had. 1 Nor was the tactical envelopment of the Russians in Augustowo Forest achieved without an extremely hazardous manceuvre. Between Feb. 15 and 18 the operations may be described as the battle of Augustowo. Few battle-stories are more complicated.
1 Railway guns were in any case unavailable, owing to the break of gauge at the frontier.
Having been joined by the Soth Res. Div. and the 4th Cav. Div. the 7Qth Res. Div. renewed its attacks on Rajgrod on Feb. 15, this time successfully. The 3rd Cav. Bde. on its right had already found its way round the S. side of Rajgrod and surprised the passage of the Augustowski canal S. of Augustowo; hither the 4th Cav. Div. followed, and the four brigades together strove to reach and bar the roads running from Augustowo south- ward and southeastward. On the opposite flank of the semicircle, the 3 ist Div. of the XXI. Corps drove on southward from the region E. of Sejny, although its outer flank almost skirted the Niemen, and reached Sopockinie (Feb. 15), barring there the most northerly of the routes leading from the forest into Grodno, but exposing its own rear to any resolute sortie from that fortress. These were the first movements towards converting the semicircle into a ring, and both then and thereafter the ring was exposed to attack from outside, against which it could scarcely have stood. The other divisions of the XXI. Corps and the XXXVIII. and XXXIX. Res. Corps meanwhile entered the forest from the N., except the yyth Res. Div., which seems to have been hastily detached to Sereje as a flank guard; for the ist Cav. Div., sth Guard Inf. Bde. and Konigsberg Land- wehr Div., already finding posts on the eastward routes at and N. of Simno, could do no more.
On Feb. 16 the battle W. and N. of Augustowo began. Here the Russians occupied a semicircular position between Bralo- brzegi, on the canal to the S. of the town, and the village of Szczebra, on the marshy Bilzna stream to the N. of it. Augus- towo itself, the most important road-centre of the region, lies in a defile formed by two E.-W. lake-chains. Behind the town, the routes to the N.E. and E. traverse this defile, then break with their respective directions over the lake-chains at the villages of Studzieniczna and Sajenek respectively. The position was attacked from the S.W. by the XL. Res. Corps from Rajgrod, the 2nd Div. on the Lyck road, and what was left of the 3rd Res. Div. and ist Landwehr Div. (the nth Landwehr Div. being taken out of the line on Feb. 15) on the Raczki road, while half of the loth Landwehr Div. approached Szczebra from the N.W., and the other half, crossing the front of the XXXVIII. Res. Corps of Eichhorn's army, came down on the same point from the north. But already on the evening of Feb. 15 a brigade of the XXI. Corps from the extreme left of Eichhorn's line, after traversing the forest diagonally from flank to flank, had reached Studzieniczna and Sajenek, and it now stood there, barring the roads immediately behind Augustowo but itself completely isolated.
This was the strangest of many strange episodes in the final phase of the Masurian winter battle. When, on Feb. 14, General von Eichhorn's army bordered the N. edge of the great forest, Fritz von Below, the commander of the XXI. Corps, sent his 3ist Div., as already mentioned, to' the S., and his 42nd Div. southeastward, into the heart of the forest. On his right the XXXIX. Res. Corps, temporarily reduced to the y8th Res. Div., barred, without advancing, the northern exits, while the XXXVIII. Res. Corps at Suwalki (aided by part of the loth Landwehr Div., VIII. Army) was forcing a way in from the N.E. corner. The general intention was thus to envelop those Russian forces remaining in the northern part of the forest. But, finding no great opposition, the 6$th Bde. of the 42d Div. the same brigade which had forced a way to Wladislawow six days before pushed on ahead past Fronczi and Serskilas, and so arrived behind Augustowo, while the brigade following it (sgth) halted about Serskilas.
Next morning, when the fighting W. of Augustowo was just beginning, the 6sth Bde. made an effort to thrust itself into the human tide which flowed eastward from that town, and even put a battalion over to the village of Sajenek to bar the last exit. But the Russians were determined to keep open their line of retreat, and while the main part of the intrusive force was pinned to its ground at Studzieniczna, the detached battalion was overrun and destroyed. Meantime the Russians in the north part of the forest, who were now retiring, before Eichhorn's frontal attack, in the direction of Grodno, came upon the 59th
