The scheme for the eastward advance, which Lord Roberts did not feel himself justified in initiating until after the affair of July 16, was that French should rejoin Hutton and take charge of the right; with Ian Hamilton, brought down from his northward demonstration against Grobler, on the extreme left north of the railway, while Pole-Carew advanced with Lord Roberts centrally along it. [Sidenote: Map, p. 292.] The advance began on July 23. French, with the natural spirit of a cavalry officer, chafed at being restricted to the slower progress of Pole-Carew's infantry and proposed to push forward boldly and cut the railway east of Middelburg, but Lord Roberts was reluctant to part with the only cavalry he had, and vetoed the movement. Botha was soon frightened out of Balmoral, which had been his Head Quarters since the battle of Diamond Hill, and which was entered by Lord Roberts on July 25. Two days later French rode into Middelburg. The eastward advance had now gained possession of eighty miles of the Delagoa Bay railway, but the De Wet trouble and the disturbed state of the Western Transvaal made the continuation of the movement unsafe, and Lord Roberts called a halt. It was also advisable to wait until supplies had been collected at Middelburg, and until Buller, who was coming up from the south, was in a position to co-operate. Lord Roberts returned to Pretoria, leaving French in charge. Ian Hamilton, the emergency man, was sent to the west to deal with Delarey and De Wet. Towards the end of August Pole-Carew advanced to near Belfast, where he hoped soon to report himself to Buller. Nearly three months had now elapsed since the battle of Diamond Hill. The progress of the Transvaal campaign was not very apparent, but it was real. Botha had been driven back along the Delagoa Bay railway, and neither the outbreaks in the Western Transvaal nor the meteoric incursion of De Wet had availed him. Nothing that had occurred elsewhere weakened the western advance to an extent that gave him an opportunity of effectively withstanding it. Buller was approaching, and Lord Roberts was no longer dependent upon one line of communication. The fugitive Free State Government had been driven into asylum with the fugitive Transvaal Government. No commandos were at large which could seriously threaten Bloemfontein, Johannesburg, or Pretoria; and the only organized body which the enemy could bring into the field was confronted by a British Army and had the barrier of the Portuguese frontier behind it. There was good hope that in a few weeks the already undermined fabric of Boerdom would totter to the ground, and that the worst that could happen was that some of the fragments might not fall clear of the British troops.