Malon); Blumentritt's "Ueber den Namen der Igorroten" in _Ausland_, no. 1, p. 17 (Stuttgart, 1882); Sawyer's _Inhabitants of the Philippines_ (New York, 1900); pp. 254-267; and Foreman's _Philippine Islands_ (London, 1890), pp. 212-215. [55] The city of Potosi in Bolivia is situated on the slope of the Cerro Gordo de Potosi, a mountain 16,152 feet high, which contains silver mines of a richness that has become proverbial; they were discovered in 1545, by an Indian. It is estimated that the silver obtained from this mountain, up to the middle of the nineteenth century, amounted to $1,600,000,000. Humboldt gives the figures for its yield, from 1566 to 1789, amounting to 60,864,359 pounds troy; see his _New Spain_ (Black's trans., London, 1811), iii, pp. 171, 172. He also endeavors to estimate (pp. 353-379) the value of the total yield from its discovery to 1789, which he places at 5,750,000,000 of livres tournois (L234,693,840 sterling). The mines now are almost abandoned, and the annual yield is about $800,000. [56] Referring to the allotment of space for freight in the regular trading fleet sent yearly to Mexico. As has been shown in preceding documents, this privilege, as the source of much profit, was restricted by the government to the citizens of the islands, among certain of whom the space was duly allotted by toneladas, each shipping goods to that extent--although many frauds were practiced, often by royal officials themselves. The stipulation in our text secured, to persons having the right to a share in this trade, the exercise of that right while absent on the Tuy expedition, the same as if they were present in Manila when the ships were laden. The _pieza_ mentioned in this paragraph was the bale used as the unit of capacity in lading the vessel (see Bourne's introduction to this series, _Vol_. I, p. 63). A letter from Andres de Alcaraz to the king (August 10, 1617), which will be presented in _Vol_. XVII, gives further information regarding the pieza. From this document it appears that the tonelada was reckoned at eight piezas; the pieza would then be estimated at ten arrobas, or two hundred and fifty libras. [57] Evidently a reference to a compilation of Spanish laws. There is nothing in the _Recopilacion de las leyes de Indias_ answering to this. [58] The district of the governor formerly called adelantado.