The main and subsidiary railroads thus summarized should, from the point of view of our subject, be considered as one, contributory to the advance of the British army over a substantially even country, which opposes few natural obstacles to such a movement, though here and there "accidents of {p.014} the ground"--a range of hills, or a dry river-bed, as at Paardeberg--may facilitate opposition by a military force. The system receives no further support until Johannesburg is reached. There the railroad from Durban comes in, and, if its carrying capacity were adequate, which is doubtful, would enable the chief base of operations and main line of communications to be shifted to the nearer locality, retaining the Cape road only as secondary. The advantage to the British of the line of invasion from Cape Town is that it crosses the mountains, which separate the coast district from the inland plateau, at such a distance from the enemy's frontier that it is impossible for the latter to offer serious resistance before the comparatively easy rolling country has been reached. It was for this reason that the decision of the Orange Free State to join in the war, while it added to the numerical resistance to be encountered by the British, had for them the compensating advantage that it removed the necessity of forcing their way over the difficult mountain ranges which separate Natal from the Transvaal. With the power of Great Britain to bring into {p.015} the field a great superiority of numbers, it is at least open to argument that the Free State, by ceasing to be neutral, relieved the enemy of a difficulty greater than that which its hostility introduced. It was for these reasons that the original British plan, as generally understood, was to make the main invasion along this line. The danger of Ladysmith, it is commonly and with probability believed, caused the momentary abandonment of this purpose. Whether the change was at the moment correct in principle or not, it is evident that Lord Roberts has reverted to the first intention; a course which enforces its accuracy with all the weight of his well-earned great renown. The other railroad system of direct importance to the military operations of the present war is the single Natal line, from Durban to Johannesburg and Pretoria, which at Ladysmith throws off a branch to the westward, crossing the mountains to Bethlehem in the Free State, and there ends, over sixty miles from the road between Bloemfontein and Pretoria. The Natal road, having been opened as lately as 1895, may be considered the {p.016} child of the Gold Fields; prior to the discovery of which, indeed, there were in the Transvaal neither products nor consumers enough to give commercial value to a railroad.