To maintain regularity in the march occasional short halts were necessary; but at 2 a.m. there was a more serious check. The torrential rain had clogged Major Benson's compass, and he became uncertain whether the column had not trended away towards the left. Major-General Wauchope sent back for Lieutenant-Colonel Ewart. After a brief consultation, a slight change of direction to the right was made. In daylight and on a level parade ground this is a very simple matter; but in darkness and during a South African tempest, it was by no means easy. The inclination to the right was given to the column. The advance was resumed. Nothing else occurred seriously to retard progress until, just as the top of Magersfontein Hill was first made visible by the lightning, a growth of mimosa bush brought the brigade to a standstill. Major-General Wauchope, had already decided to deploy. To hasten this, he himself led the Black Watch in single file through the bush, and desired Lieutenant-Colonel Ewart to guide the remainder of the brigade round the obstruction. The three battalions in rear, easily avoiding the small patch of thorny shrubs, rejoined more quickly than had been expected, and soon fell into their proper places. When the brigade-major reported their arrival, Major-General Wauchope issued instructions for deployment on the Black Watch, but not in the same order of battalions as he had laid down on the previous day.[202] The Seaforth Highlanders were now to come up on the left, the Argyll and Sutherland on the right, of the battalion of formation. Major-General Wauchope had originally intended that both the Seaforth and the Argyll and Sutherland should prolong the left of the Black Watch, each having two companies in the firing line, two in support and four in reserve. According to this design the twelve reserve companies were to have been formed in two ranks, and were to have occupied approximately the same space from flank to flank as that covered by the six companies in the firing line. The Highland Light Infantry was intended to act as the reserve to the brigade. The presumption is that he changed his plan at the last moment, in the hope of ensuring that his right should completely overlap the eastern flank of Magersfontein Hill. [Footnote 202: See p. 312.] [Sidenote: 4 a.m. the Boers smite the brigade in the act of deploying. The consequent rush forward.]