Most of the fugitive commandos had, however, retired into the S.E. corner of the Transvaal; a movement which Hildyard, who was in charge of the district as well as of the whole of Natal, was not strong enough to check. French was now based on Natal for supplies, and arrangements had been made that two large convoys should be sent to him by way of Utrecht. Bad roads, bad weather, and submerged drifts impeded the progress of the painful trains, the first of which did not reach him until March 2, ten days after it was due. Meanwhile he subsisted on dwindled rations and on what he could pick up on the veld.
When, owing to a change in the routes by which he was supplied, French was able towards the end of March to operate actively, he endeavoured to isolate the S.E. corner of the Transvaal by disposing his force in two lines. One line ran from Piet Retief to Vryheid and acted as the driving force, and the other ran from Piet Retief along the Swaziland border and acted as the stopping force. Within the angle enclosed by these lines were commandos under Grobler of Vryheid, Emmett, and other leaders; but all of them wriggled out with insignificant losses. The line along the Swaziland border was rendered immobile by difficulties of supply, and the driving line was exhausted. The closing incident of French's ten weeks' campaign, the chief harvest of which was the capture, surrender, wounding, or killing of 1,300 Boers, the seizure of a considerable amount of ammunition, and the taking of eleven guns, was the return of Smith-Dorrien to the Delagoa Bay Railway in the middle of April.
Botha's projected invasion of Natal had indeed been frustrated and postponed, but he and all the other Boer leaders had escaped, unscathed and undismayed. French's ponderous columns had trudged painfully across the veld from Springs almost into Zululand, and had left things much as they were at the beginning of February.
During the early months of the year 1901 Viljoen for the most part contented himself with frequent attacks on the Delagoa Bay Railway, and a vigorous effort to restrain his activity was not practicable. In March Lord Kitchener formulated a plan for the subjugation of the Northern Transvaal. His plan was to send a column with secrecy and dispatch to Pietersburg, which would be occupied as a base from which the column would work southwards along the line of the Olifant's River, in co-operation with columns acting northwards from the Delagoa Bay Railway.
The force selected to proceed to Pietersburg was Plumer's Australian column, which sixteen days after it desisted from the chase of De Wet in the Orange River Colony was marching northwards out of Pretoria. Plumer entered Pietersburg on April 8 without opposition, Beyers, who had been falling back before him from Warmbaths, having evacuated the town. Plumer halted for a few days in order to secure the railway and to make arrangements for carrying out his orders to hold the line of the Olifant's River. Before the end of the month he was in possession of all the drifts from Commissie Drift downwards, and denied them to Viljoen.
The country in which Viljoen was acting is hilly and intricate, and Lord Kitchener, by borrowing Sir Bindon Blood from the Indian Government, an officer of great experience in frontier guerilla, paid Viljoen and the Boer commandos the compliment of crediting them with the military qualities of the dangerous, predatory, and enterprising hill tribes of the underfeatures of the Himalayas. To Blood were given six columns which were to work from Lydenburg and the Delagoa Bay Railway.
Viljoen was near Ros Senekal. He had three lines of retreat, northward or southward along the Steelpoort River, or down the Blood River. Blood's columns were disposed with the object of closing these exits. The Transvaal Government, which for some months had been sojourning in security at Paardeplatz, fled and joined Botha near Ermelo; but Viljoen stood fast.
The total force under Blood exceeded 10,000 men. Three columns under Beatson, Benson, and Pulteney, who had joined from Vryheid where he had been serving under French's command, advanced northwards from the Delagoa Bay Railway. On their right front they were supported by three columns acting from Lydenburg, under Park, W. Douglas, and W. Kitchener. Douglas was the only leader destined to encounter Viljoen, who on April 10 struck at him near Dullstroom, but was handsomely beaten and compelled to return to the place from which he came. He was hedged in on all sides; mutiny and disaffection were rife among his burghers; and he saw that there was nothing to be done but make his escape as best he could.
He was headed off by Benson in an attempt to get away up the Steelpoort Valley, where next day 100 Boers gave themselves up to Blood. He next tried the Blood River, and passing down the valley crossed the Olifant on April 22, almost within sight of Beatson, who was watching the drifts. A few days later he crossed the railway and joined Botha at Ermelo. Early in May the active operations north of the Delagoa Bay Railway ceased. As in French's campaign, so also in Blood's, the results were chiefly negative. A glut of live stock was rounded up, a considerable amount of ammunition and all the guns known to be in the district were taken, and 1,100 Boers either surrendered or were made prisoners. The columns were withdrawn, as troops were in request in the districts lately driven by French; and Plumer, who had had no opportunity of engaging actively in the movement, was recalled. He was succeeded at Pietersburg by Grenfell.
At the end of May Dixon set out westwards from Naauwpoort in the Magaliesberg district on a raiding expedition. He trekked for three days and then ran unexpectedly into a Boer column at Vlakfontein. He was attacked through a veil of smoke from a grass fire which the slim enemy had lit to windward. In spite of this disadvantage he held his own and compelled the Boers to retire, but soon, however, found it advisable to retire himself and returned to Naauwpoort.