It was now evident that De Wet's objective was the Zand Drift on the Orange west of Phillipolis. He had had a long start, and the nearest troops available for the pursuit of him were the columns of Knox and Hamilton at Bethulie. Here the river bends round to the south, forming an arc through Norval's Pont towards Zand Drift; and the columns therefore crossed to the right bank and marched eighty miles along the chord, only to find when they reached the Drift on February 12 that De Wet had two days previously crossed by it into the Cape Colony. The operations of the next sixteen days were confined to a comparatively small rectangle of about 6,000 square miles lying on the left bank of the Orange, which bounded it from Norval's Pont to Douglas and thence to near Prieska. The S.E. side and half the S.W. side, namely from Norval's Pont to Naauwpoort and thence to De Aar, were formed by the railways, the remaining portion of the S.W. side being the river Brak, which flows into the Orange a few miles above Prieska. Owing to a sudden flood, which delayed Knox for two days, he was unable to follow De Wet across Zand Drift, but Plumer started from Naauwpoort with two columns, and on February 12 came in touch with De Wet and compelled him to change his course. Two days later De Wet crossed the railway between De Aar and Hopetown, after a rearguard action with Plumer, into whose hands fell next morning the transport which De Wet had been compelled by bad weather to leave behind him. De Wet now proposed to fetch a compass towards Prieska, where he hoped to effect a junction with Hertzog, but the driving power of the raid was slowly exhausting itself. The motive energy was stored up in accumulators, and when these were discharged in succession, there was no means of re-charging them. Hertzog and Kritzinger, who had been relied on for this purpose, were not at hand; more than a third of the force with which De Wet had originally left the Doornberg had declined to leave the Free State; and the transport had been lost.