'Earth which contains only one-twenty-fifth part of a grain of gold, equal to one-fifth of a cent in value to the bushel, may be profitably washed by this method; and any earth or gravel which will pay the expense of washing in the old way gives enormous profits by the new process. To wash successfully in this way requires a plentiful supply of water, at an elevation of from fifty to ninety feet above the bed-rock, [Footnote: This is by no means necessary. The jet can be thrown from below like the fireman's hose playing upon a burning house. I shall return to this highly important subject.] and a rapid slope or descent from the base of the bank of earth to be washed, so that the waste water will run off through the sluices, bearing with it gravel, sand, and suspended clay. * * * * * 'In the case of a deposit in North Carolina, where ten men were required for thirty-five days to dig the earth with pick and shovel and wash it in sluices, two men with a single jet of water could accomplish the same work in a week. The great economy of this method is manifest from the fact that many old deposits in the river-beds, the gravel of which had been already washed by hand, have again been washed with profit by the hydraulic method. 'In California the whole art of working the diluvial gold-deposits was revolutionised by this new method. The auriferous earth lying on hills and at some distance above the level of the watercourses would in the ordinary methods be excavated by hand and brought to the water, but by the present system the water is brought by aqueducts to the gold-deposits, and whole square miles which were before inaccessible have yielded up their precious metal. It sometimes happens from the irregular distribution of the gold in the diluvium in California that the upper portions of a deposit do not contain gold enough to be washed by the ordinary methods, and would thus have to be removed at a considerable expense in order to reach the richer portion below. By the hydraulic method, however, the cost of cutting away and excavating is so trifling that there is scarcely any bank of earth which will not pay the expense of washing down in order to reach the rich deposits of gold beneath.' To conclude. Our collection of plants was sent to the Herbarium, Kew; and, as the Appendix (II. Part II.) shows, was kindly catalogued by the learned Professor D. Oliver. CHAPTER XX. FROM AXIM TO INGOTRO AND AKANKON. After a long palaver with the three claimants to the Akankon mining-ground, Kofi Blaychi (Little Blay), Kwako Jum, and Safahin Sensense (the lessor), we left Axim once more (February 24) to inspect the head of the Ancobra river. At the sleeping-place, Kumprasi, we were visited by Mr. Cascaden, District-commissioner for Takwa, a fine-looking man of fifteen stone, pulled down to twelve by dysentery. He was speedily followed to England by his _remplacant_, Dr. Duke.