The African differs from the Asiatic in the formation of ivory, the tusks of the former being both thicker and heavier; the females also possess tusks, whereas those of the Asiatic variety have merely embryo tusks, which do not project more than two or three inches beyond the lips. I had a tusk of an African elephant that weighed 149 lbs. I have seen in Khartoum a pair that weighed 300 lbs., and I saw a single tusk of 172 lbs. In 1874 a tusk was sold at the ivory sale in London that weighed 188 lbs. These specimens are exceptions to the general rule, as the average weight in a full-grown African male would be about 140 lbs. the pair, or 75 lbs. for one tusk and 65 lbs. for the fellow, which is specially employed for digging. The African variety is an industrious digger, as it feeds upon the succulent roots of many trees, especially those of the mimosa family. The right tusk is generally used in these operations more than the left; accordingly it is lighter from continual wear, and it is known by the Arabs as the "hadam" or servant. As the African elephant is a root-eater it is far more destructive than the Asiatic. It is astonishing to observe the waste of trees that are upturned by a large herd of these animals, sometimes out of sheer wantonness, during their passage through a forest. The dense tops of mimosas are a great attraction, and there can be no doubt that elephants work collectively to dig out and to overthrow the trees that would be too large for the strength of a single animal. I have seen trees between two and three feet in diameter that have been felled for the sake of the roots and tender heads; these have shown unmistakable signs of an attack by several elephants, as the ground has been ploughed by tusks of different sizes to tear up the long straggling roots which were near the surface, and the deep marks of feet around the centre of operations, of various diameters, have proved the co-operation of members of the herd. I once saw an elephant strike a large timber tree with its forehead to shake down the fruit. This was a peculiar example of the immense power that can be exerted when required. We were waiting near the margin of the White Nile, about half an hour before sunset, expecting the arrival of waterbuck, when a rumbling sound and a suppressed roar in the jungle were accompanied by the breaking of a branch, which denoted the approach of elephants. Presently they emerged from the forest in several directions, and one, which appeared to be the largest I had ever seen, advanced to within 120 yards of our position without perceiving us, as we were concealed behind a bush upon some rising ground close to the river's bank. This elephant had enormous tusks, but as we had only small-bore rifles, I was contented to watch, without disturbing the magnificent animal before me.