When they had left next morning to resume their journey, I started out and made a search up and down the river for the proper position for my temporary bridge. After a thorough examination of all the possible situations, I chose the most suitable and pitched my tent close to it for a night or two while I made the necessary calculations for carrying out the work. The crossing on which I had decided had to be approached by a somewhat sharp curve in the line, and in laying this out with the theodolite I experienced considerable difficulty, as for some reason or other I could not make the last peg on the curve come anywhere near the tangent point where the curve should link up with the straight. I repeated the whole operation time after time, but always with the same result. Eventually I came to the conclusion that there must be some mistake in the table of angles from which I had been working, so I started to work them out for myself and soon discovered a serious misprint. This being rectified in my calculations, I proceeded to lay out the curve again, when at last everything came out accurately and to my satisfaction. After I had pegged out this temporary diversion of the line, I thought I richly deserved a few hours' play, and accordingly determined to try my luck after lions up-stream towards the source of the Athi. The river--which runs almost due north here, before taking a turn eastward to the Indian Ocean--forms part of the western boundary of the Athi Plains, and is fringed all along its course by a belt of thorny hardwood trees. In some places this fringe is quite narrow, while in others it is about a quarter of a mile wide, with grassy glades here and there among the trees. Every now and again, too, the stream itself widens out into a broad stretch of water, nearly always covered over with tall reeds and elephant grass, while along the banks are frequent patches of stunted bushes, which struck me as very likely places for the king of beasts to sleep in after having drunk at the river. I had noticed that after having eaten and drunk well, a lion would throw himself down quite without caution in the first shady spot he came to; of course nothing except man ever disturbs him, and even of man the lions in this part of the country had as yet no fear, for they had rarely if ever been hunted previous to my time.