Both previous to the successful and unresisted crossing of the Tugela, as well as subsequently, frequent rains had caused great discomfort to the troops, as well as immensely increased the difficulties of transport. The _impedimenta_ of the large force in the field was exceedingly great, and the want of knowledge of the character of the roads, or tracks, and the capacity of oxen to do the work, resulted in many delays and difficulties. Large masses of infantry were moved into the enemy's country, whose entire dependence for supplies was placed upon heavy waggons drawn by numerous oxen. No system of carriers was established, and, with the exception of the fourth (Wood's) column, the movement of the troops was necessarily exceedingly slow. On the march each column was exposed to be attacked at a disadvantage, so enormous was the train of waggons which had to be guarded, and the knowledge of these facts evidently enabled the Zulus to perceive the best opportunity of striking a fatal blow. At a very early stage in the war, Lord Chelmsford saw the difficulties connected with the mode of supplies adopted, as he writes on the 16th of January, "It would be impossible to keep a long line of road passable for a convoy of waggons, and were we to advance far into the country it would be almost certain that, instead of our supplies coming to us, we should have to return for our supplies." [Sidenote: _Zulu tactics._] The country into which the British troops had entered was one in which the mountain-sides are furrowed by deep kloofs or ravines, generally covered by luxuriant vegetation. The euphorbia, the cactus, the aloe, and mimosa grow in profusion, and the bush in many places forms a natural fortress, in which savages can easily lie in wait to surprise an enemy. It was in such native fastnesses that the Kafirs of the Cape Colony loved to wait—panther-like—either in war to attack the white man, or in peace to rob his flocks and herds. The Zulus, however, fortunately adopted tactics of a different character. Their plan was to attack in the open field, and, by means of bravery and overwhelming numbers, to entirely crush the enemy. It was thus that Chaka had conquered, and it was upon the same system that Cetywayo relied. CHAPTER IV. LORD CHELMSFORD'S PLANS—THE BATTLE OF ISANDHLWANA—THE HEROIC DEFENCE OF RORKE'S DRIFT—PANIC IN THE COLONY—REQUEST FOR REINFORCEMENTS—REPLY FROM THE QUEEN—THE MINISTRY—SIR BARTLE FRERE—LORD CHELMSFORD. It is desirable for the sake of justice that the plans of Lord Chelmsford in commencing the campaign should be given in his own words. They are contained in a memorandum dated 16th January, 1879, and are as follows:— "The reports which I receive from officers commanding the several columns now operating against Cetywayo show clearly that at this season of the year a rapid advance into the heart of Zululand is absolutely impossible.