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 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 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.

The Cape Town line reached Pretoria only in 1892, and it is still characteristic of all the lines that there is but little local traffic, either freight or passenger; the roads exist as means whereby the function of communication, so far discharged by the sea, is prolonged from the coast to the interior of the continent.

It is not the least noteworthy in the incidents of commercial and mechanical energy, by which foreign hands have developed the Transvaal from a poor to a wealthy state, that "all the heavy machinery, the timber, the corrugated iron with which the works and men's houses are constructed, and nearly every requirement of work and life, had to be brought for over three hundred miles upon ox-wagons, the country itself supplying scarcely anything, and even to this day (1897) wheat being brought from Australia."[1]

Regarded as a source of supply, especially of military supply, the demands of which are more urgent than those of common life, as its needs and dangers are more imminent, the Natal railroad, though much shorter in distance to the probable scenes of operations, labours under two disadvantages. The port of Durban is not under all circumstances safe for large vessels to enter, and there is therefore in the facilities for landing goods an inferiority to Cape Town. The country, too, is more difficult, the obstacles to movement, which also favour defence, increasing as the frontier is approached, and culminating on the borders of the Free State and the Transvaal. Being thus nearer, the latter are here better able to concentrate and sustain opposition than they are on the western flank.

"The mountains which on the edge of Basutoland rise to a height of ten thousand feet," writes Mr. Bryce, "break down toward Natal in tremendous precipices. Near Ladysmith the frontier of the Orange Free State coincides with a high watershed, crossed by only a few passes."[2] Where this boundary between Natal and the Free State ends, that of the Transvaal begins, and soon after turns sharply to the southward, the new direction forming with the old a very acute angle, with apex to the north. Here, just within the territory of Natal, is Majuba Hill, whose name has been in the mouths of all men, and Laing's Nek, less familiarly known. The narrow neck of rugged country embraced between the legs of this angle is about sixty miles long, from Majuba to Glencoe. Recent events have familiarised to us many of the names along this line of rail—Glencoe, Dundee (the terminus of a short branch), Colenso, Estcourt, and Ladysmith itself; while the winding character of the track, as mapped, compared with the Free State road, sufficiently indicates the character of the country, in which obstacles have to be circumvented as well as overcome. The grade is in places as high as one in thirty, though that is being reduced; but one in forty is common. Pietermaritzburg, the capital, fifty miles from Durban in a straight line, is 2,200 feet above the sea. Three hundred miles from its starting-point the road reaches an elevation of over five thousand feet, at Laing's Nek, through which it passes by a tunnel.

A topographical map of the country shows upon examination that the mountain range, which forms the western boundary of Natal toward Basutoland and the Orange Free State, and has a general north and south direction parallel to the railroad, throws off to the eastward spurs which, to repeat Mr. Bryce's expression, "break down in tremendous precipices," forming a succession of terraces. The gorges between these determine the direction of the river-beds whereby the rainfall pours down to the sea; and the general easterly course thus imparted is maintained and continued by the lie of the valleys, separating the successive hills through which the territory of Natal gradually rises to the northward. These various streams find their way sooner or later to the Tugela, itself one of the many, but which carries its own name until it reaches the Indian Ocean, some fifty miles north-east of Durban.

Of these watercourses, the Tugela, which the road crosses at Colenso, and the Mooi, some fifty miles south, have been most often mentioned. Another tributary called the Klip flows through the camp at Ladysmith. The channels which these streams have cut for themselves in time of torrent are both steep-banked and deep. They are therefore among those accidents of the ground which, duly improved, can seriously affect military operations. The destruction of a bridge impedes the transport of troops and supplies; a sudden freshet, occurring in the midst of an extensive movement, may imperil an army by sundering its forces; while of the utility of such natural trenches to the purposes of shelter and of defence, of awaiting attack, or resisting an advance, both the Tugela and Paardeberg have given recent striking illustration.

As a general rule such conditions favour the defence relatively to the offence; the former, remaining comparatively motionless, is shielded by obstacles, to surmount which the assailant must expose himself in the open. Thus they compensate for inferior numbers, which is usually the condition of the defence; and they conduce to delay, ever a leading object in defensive warfare. Consequently, in the present hostilities they have helped the Boers. It may be added that their influence is most felt when the armies are face to face, or at least in touch. Hence their existence near the scene of probable conflict, as in Natal, is a matter of more concern to the invader than when, as upon the Cape extreme of the scene of war, they are found beyond the range to which the defendant can safely extend his operations.