There would be in all nineteen charges to explode, and these were in three groups at some little distance from each other, all the cannon being on the same siding. It would be necessary, perhaps, to wait for some time till all these were free from observation by natives or others who might be moving about the yard, then a signal must be given that they could all see. It would not take long to light the fuses, for each of them would be provided with a slow match, which burns with but a spark, and could be held under a hat or an inverted tin cup till the time came for using it. The question was how far must they be away to ensure their own safety, and Chris maintained that at least four or five hundred yards would be necessary to place them in even comparative safety from the rain of fragments that would fall over a wide area. Finally it was agreed to cut the fuses to a length to burn four minutes; this would allow a minute for any hitch that might occur in lighting them, and three minutes to burn. It was of course important that they should be no longer than was absolutely necessary, as there existed a certain risk that one of the little sparks might be seen by a passing Kaffir, or, as was still more probable, the smell of burning powder should attract attention. It was agreed that Chris should light the fuses at the cannon, which were farthest from the others, that Peters should see to the six rifle trucks, and Willesden and Brown attend the eight trucks with the ammunition, one to begin at each end of the line. When each had finished his work, he was to run straight away in the direction of the encampment, and all were to throw themselves down when they felt sure that the time for the explosions had arrived. As soon as all was over they were to meet at their place of encampment. Tents and all stores were to be removed before the work began to the ravine where the horses were, the men with them being charged to stand at the animals' heads, as there would be a great explosion, and the horses might break loose and stampede. The matter that puzzled them the most was how, when they reached their respective stations--separated from each other by lines of waggons, and in some cases by distances of a couple of hundred yards--they were to know when the work of lighting the fuses was to begin. It could not be done by sound, for this would reach the ears of any awake in the yard or the sentries at the bridge. Chris at last suggested a plan.