Lord Roberts had sent Kitchener with a column to see to the trouble in the Free State, and could not put more than about 16,000 men into the field against Botha, who, with 6,000 men, had taken up a strong position astride the Delagoa Bay railway sixteen miles east of Pretoria. His centre was at Pienaar's Poort, where the railway passes through a defile, and his front, which his former experience of Lord Roberts' tactics led him to extend greatly, was nearly twenty-five miles in length, and ran along an irregular chain of hills, kopjes, and ridges. Facing the Diamond Hill and Donkerhoek range, south of the centre, is another range of heights through which the two poorts Tyger and Zwavel pass, and which circles round the source of Pienaar's River towards the Diamond Hill range. North of the centre runs a broken range ending abruptly at the Kameelfontein ridge, which overlooks the broad Kameelfontein valley leading to the Krokodil Spruit; and across the valley rises the Boekenhoutskloof ridge, a detached feature with triangular contours, which, being somewhat in advance, commands the approaches to Kameelfontein ridge, where the Boer right flank under Delarey was posted. The left flank was on Mors Kop and curved round indefinitely to Kameelzyn Kraal with detached posts in the direction of Tygerpoort. The centre north and south of Pienaar's Poort was the strongest section of the line, and for this reason and for another it was held by comparatively small numbers. Botha was an acute observer and had learnt the moves of the British autumn manoeuvre opening, a holding attack on the centre not intended to be pushed home in order to eke out paucity of numbers operating on a wide front. Lord Roberts, in spite of his superiority of strength, could not hope to inflict a decisive defeat upon Botha's well-posted commandos, but only to remove them out of striking distance of Pretoria, and he was successful. The earlier movements of the attack on June 11 were in the nature of a reconnaissance in force, as it was uncertain how far to the north and south the Boer front extended. The usual tactics were adopted. French with the 1st and 4th Cavalry Brigades under Porter and Dickson was to work round the enemy's right flank and to endeavour to circle round it to the railway; a demonstrating attack on the centre would be made by Pole-Carew; while Ian Hamilton acted against the left flank.