[Illustration: PERUVIAN DRINKING VESSEL. [After a cut in Wilson’s _Prehistoric Man_, ii. 45; showing a cup of the Beckford collection. “There is an individuality in the head, at once suggestive of portraiture.”—ED.]] The artificers engaged in the numerous arts and on public works subsisted on the government share of the produce. The artists who fashioned the stones of the Sillustani towers or of the Cuzco temple with scientific accuracy before they were fixed in their places, were wholly devoted to their art. Food and clothing had to be provided for them, and for the miners, weavers, and potters. Gold was obtained by the Incas in immense quantities by washing the sands of the rivers which flowed through the forest-covered province of Caravaya. Silver was extracted from the ore by means of blasting-furnaces called _huayra_; for, although quicksilver was known and used as a coloring material, its properties for refining silver do not appear to have been discovered. Copper was abundant in the Collao and in Charcas, and tin was found in the hills on the east side of Lake Titicaca, which enabled the Peruvians to use bronze very extensively.[1221] Lead was also known to them. Skilful workers in metals fashioned the vases and other utensils for the use of the Inca and of the temples, forged the arms of the soldiers and the implements of husbandry, and stamped or chased the ceremonial breastplates, _topus_, girdles, and chains. The bronze and copper warlike instruments, which were star-shaped and used as clubs, fixed at the ends of staves, were cast in moulds. One of these club-heads, now in the Cambridge collection, has six rays, broad and flat, and terminating in rounded points. Each ray represents a human head, the face on one surface and the hair and back of the head on the other. This specimen was undoubtedly cast in a mould. “It is,” says Professor Putnam, “a good illustration of the knowledge which the ancient Peruvians had of the methods of working metals and of the difficult art of casting copper.”[1222] [Illustration: UNFINISHED CLOTH FOUND AT PACHACAMAC. [After a cut in Wiener, _Pérou et Bolivie_, p. 65.—ED.]]