The enemy, however, again evaded the net. Reconnaissances by French on May 23 showed that Botha had been frightened by the appearance of Ian Hamilton at Heilbron, and had crossed into the Transvaal. The discovery necessitated the recasting of Lord Roberts' plan, and brought about an interesting and entirely successful strategic movement. It was evident from Botha's dispositions that he expected Ian Hamilton to march straight to his front and endeavour to cross the Vaal above the railway bridge at Vereeniging. The difficult drifts and country below it were considered to be a sufficient protection, and were not strongly held by Botha, who on this occasion was completely out-generalled by his opponent.
Lord Roberts ordered Ian Hamilton to march from the right flank to the left, across the front of the main Army, and then in conjunction with French to wheel round to Meyerton on the line between Johannesburg and Vereeniging. On the evening of May 26 he entered the Transvaal at Wonderwater Drift. But Ian Hamilton's column had not the honour of being the first troops of the main body to enter the Transvaal, for he found the cavalry in front of him. French,[43] who had been sent out from Kroonstad on May 20, reached the Vaal at Paris on the 24th, and at once threw part of his force into the Transvaal, the rest crossing higher up at Old Viljoen's Drift. He thus fittingly celebrated the last birthday festival of Queen Victoria, which was also appropriately honoured by a proclamation issued on the same day by Lord Roberts, by which the Orange Free State was annexed to the dominions of Her Majesty under the designation of the Orange River Colony—a suitable birthday offering from a distinguished soldier to his Sovereign.
The main body of the Army with the Commander-in-Chief at its head entered the Transvaal at Viljoen's Drift on May 27, and, like the pioneer columns of French and Ian Hamilton, met with no opposition. It was of good augury for the speedy subjugation of the South African Republic. The expected firm stand of the enemy along the right bank of the Vaal, where the great battle of the war was to be fought, was not made. Vereeniging and subsequently Meyerton were abandoned in spite of all Botha's efforts to keep his burghers' faces to the front. He held a strong line enclosing Vereeniging and the drifts and extending from near Heidelberg to Potchefstroom, but it impotently watched the British troops crossing the river. Some opposition was indeed offered to French when he was a day's march from the drift by which he had crossed into the Transvaal, but the bulk of the commandos fell away to the north and took up positions between Johannesburg and Krugersdorp. By arrangement between the Governments, none of the Free Staters accompanied Botha into the Transvaal; but he was in communication with De Wet at Frankfort, and was urging him to act against the railway in the Free State. He must have regretted that the strong hand and will of the man of Waterval Drift, Kitchener's Kopje, Sannah's Post, and Mostert's Hoek, were not with him on the right bank of the Vaal to animate the shrinking burghers of the South African Republic.
The immediate purpose of Lord Roberts was now the capture of Johannesburg, the relations of some of whose inhabitants towards Pretoria had brought on, not only the Jameson raid, but also the war. Although it was not defended by permanent military works, the burghers had taken up a position before it which might be very hard to capture, and there was another and greater cause for anxiety. The task before Lord Roberts may be likened to an attack on a ship manned by pirates, who threaten to fire the magazine as soon as a hand is laid upon the bulwarks. It was seriously proposed by certain persons in authority under Kruger, that on the appearance of the British Army before the city, the mines in which so many millions of British capital were invested should be wrecked; and it is probable that the threat would have been carried out with official sanction if Botha had not set his face resolutely against such a piratical act.
Lord Roberts proposed to effect the capture of Johannesburg by surrounding it. While with the main body of his Army he occupied Elandsfontein on the east, French and Ian Hamilton, the pioneers of the advance from Bloemfontein, would deal with the enemy posted south of the city and then establish themselves, the former near Klipfontein, north of it, and the latter near Florida, west of it. The right and the most vulnerable part of the Boer line was posted on Doornkop near the scene of the surrender of Jameson, the enthusiast, who, a few years before, had endeavoured with a few hundred adventurers and soldiers of fortune to solve the South African question which Great Britain was now tackling with a quarter of a million of trained soldiers.
On May 29 Ian Hamilton attacked the Doornkop position and won it after some hard infantry fighting; French, reinforced by the loan of Hamilton's mounted troops, having thrown a grappling iron round it, thereby rendering it untenable. At nightfall the two leaders were firmly planted west of the city. The movement deceived the enemy, to whom the advance of the main body under Lord Roberts on Elandsfontein came as an unwelcome surprise, though Botha had to some extent prepared for it. The detachments posted by him at various places east of the city offered no effectual resistance, and Lord Roberts went into bivouac that night at Elandsfontein. Johannesburg was entrapped between him on the east, and French and Hamilton on the north and west.
On May 30 the city agreed not unwillingly to surrender, but having regard to the presence in it of splinters of the lately shattered commandos, to the probability of street fighting, and to the risk of injury to the mines, Lord Roberts consented to postpone his formal entry until the following day; by which time the judicious action of the representatives of the Boer Government had averted the impending danger, and the troops took peaceful possession of Johannesburg.
In spite of disquieting news from the Free State, Lord Roberts remained firm in his purpose of advancing on Pretoria without delay. Not only was it the head quarters of Krugerism, but also the place in which the Boer harvest of war—more than 4,000 British prisoners, some of whom had been in captivity since the day of Talana Hill—was garnered.
On June 3 the advance on Pretoria, which it was hoped would be the last important movement of the war, was resumed; Wavell, with a brigade of Tucker's Division, being left behind as Bank Guard over the treasure in the mines. Botha had retired on the capital, but no one knew whether he would endeavour to defend it, or whether the vaunted forts would imperiously address the invader. In view of possible eventualities, however, a siege train, in which were included two 9.45" howitzers which had been hastily acquired in Austria, was taken up to answer Forts Schanzkop, Klapperkop, Wonderboom, and Daspoort if they should speak.