Though Hertzog at Calvinia and De Lisle at Clanwilliam were only fifty miles apart, the intervening country is among the most broken and mountainous in South Africa. Between the two points, and nearer to De Lisle than to Hertzog, flows the Doorn River. The Boers advancing from Calvinia came into touch with the British scouts at this point, and drove them in upon January 21st. On the 28th De Lisle, having been reinforced by Bethune's column, was able at last to take the initiative. Bethune's force consisted mainly of Colonials, and included Kitchener's Fighting Scouts, the Cape Mounted Police, Cape Mounted Rifles, Brabant's Horse, and the Diamond Field Horse. At the end of January the united forces of Bethune and of De Lisle advanced upon Calvinia. The difficulties lay rather in the impassable country than in the resistance of an enemy who was determined to refuse battle. On February 6th, after a fine march, De Lisle and his men took possession of Calvinia, which had been abandoned by the Boers. It is painful to add that during the month that they had held the town they appear to have behaved with great harshness, especially to the kaffirs. The flogging and shooting of a coloured man named Esan forms one more incident in the dark story of the Boer and his relations to the native.
The British were now sweeping north on a very extended front. Colenbrander had occupied Van Rhyns Dorp, to the east of Calvinia, while Bethune's force was operating to the west of it. De Lisle hardly halted at Calvinia, but pushed onwards to Williston, covering seventy-two miles of broken country in forty-eight hours, one of the most amazing performances of the war. Quick as he was, the Boers were quicker still, and during his northward march he does not appear to have actually come into contact with them. Their line of retreat lay through Carnarvon, and upon February 22nd they crossed the railway line to the north of De Aar, and joined upon February 26th the new invading force under De Wet, who had now crossed the Orange River. De Lisle, who had passed over five hundred miles of barren country since he advanced from Piquetburg, made for the railway at Victoria West, and was despatched from that place on February 22nd to the scene of action in the north. From all parts Boer and Briton were concentrating in their effort to aid or to repel the inroad of the famous guerilla.
Before describing this attempt it would be well to trace the progress of the eastern invasion (Kritzinger's), a movement which may be treated rapidly, since it led to no particular military result at that time, though it lasted long after Hertzog's force had been finally dissipated. Several small columns, those of Williams, Byng, Grenfell, and Lowe, all under the direction of Haig, were organised to drive back these commandos; but so nimble were the invaders, so vast the distances and so broken the country, that it was seldom that the forces came into contact. The operations were conducted over a portion of the Colony which is strongly Dutch in sympathy, and the enemy, though they do not appear to have obtained any large number of recruits, were able to gather stores, horses, and information wherever they went.
When last mentioned Kritzinger's men had crossed the railway north of Rosmead on December 30th, and held up a train containing some Colonial troops. From then onwards a part of them remained in the Middelburg and Graaf-Reinet districts, while part moved towards the south. On January 11th there was a sharp skirmish near Murraysburg, in which Byng's column was engaged, at the cost of twenty casualties, all of Brabant's or the South African Light Horse. On the 16th a very rapid movement towards the south began. On that date Boers appeared at Aberdeen, and on the 18th at Willowmore, having covered seventy miles in two days. Their long, thin line was shredded out over 150 miles, and from Maraisburg, in the north, to Uniondale, which is only thirty miles from the coast, there was rumour of their presence. In this wild district and in that of Oudtshoorn the Boer vanguard flitted in and out of the hills, Haig's column striving hard to bring them to an action. So well-informed were the invaders that they were always able to avoid the British concentrations, while if a British outpost or patrol was left exposed it was fortunate if it escaped disaster. On February 6th a small body of twenty-five of the 7th King's Dragoon Guards and of the West Australians, under Captain Oliver, were overwhelmed at Klipplaat, after a very fine defence, in which they held their own against 200 Boers for eight hours, and lost nearly fifty per cent of their number. On the 12th a patrol of yeomanry was surprised and taken near Willowmore.