In former days gold was extensively washed by Chinese at Bau and Paku in Upper Sarawak, which auriferous district commences at the confluence of the two branches of the Sarawak river, and extends back to their sources and the boundary of Dutch Borneo. As gold and antimony were known to abound here, the Chinese of Sambas and the lower Kapuas had made several endeavours to establish themselves in the district, but were much harassed by the Malays until the accession of the late Rajah Brooke, which made it possible for them to settle there and pursue in peace their business of gold mining. Then gold was washed extensively, and the fine reservoirs and "leats" which the Chinese constructed to sluice the alluvial soil remain to this day. They increased and became a thriving community, but they were not sufficiently looked after, and, falling under the machinations of socialistic Secret Societies, gradually got out of hand and broke into open rebellion in 1857, as shall be related in the sequel. It is sufficient to say here that this ended in dire ruin to themselves, and that the few who escaped were driven over the borders; but it also ruined the gold-mining industry, and, though some of the rebels returned and others came with them, the industry never fully recovered, and later on it received a further check by the introduction of pepper planting, which gave the Chinese a more profitable occupation, and gradually Upper Sarawak became covered with gardens of this description. Though gold mining under the Chinese practically died out, modern scientific and engineering skill has now placed it in a far higher position than it had ever previously attained, or could have attained under the primitive methods of the previous workers. Quicksilver was discovered _in situ_ about the year 1871, by Messrs. Helms and Walters of the Borneo Company, who prospected over the whole of Sarawak Proper, and ultimately succeeded in tracking the small fragments of cinnabar that are scattered over the district to a hill on the right bank of the Staat river. The hill is called Tegora, and rises to an elevation of 800 feet. In the upper portion of this hill, the ore was found deposited capriciously in strains and pockets with here and there a little metallic mercury.[9]