Jaen, the place where these mines were situated is at present totally unknown. The veins of cinnabar of Guaraz were worked with some de

gree of success in 1802.

There was extracted

as much as 84 pounds of mercury from a mass of minerals of 1500 pounds weight.

The famous mine of Huancavelica, as to the state of which so many erroneous ideas have been disseminated, is in the mountain of Santa Barbara, to the south of the town of Huancavelica, at a horizontal distance of 2772 varas (or 2319 metres *). The height of the town above the level of the sea, is according to Le Gentil 3752 metres (1925 toises). If we add to this the 802 varas, which the summit of the mountain of Santa Barbara is higher than the level of the streets of Huancavelica, we shall find the absolute height of this

+ This height is calculated agreeably to the formula of M. La Place, supposing a temperature of 10 centigrade degrees (50° Fahr.) According to Le Gentil, (Voyage aux Indes, t.i. p. 76.) the mean height of the barometer at the town of Huancavelica is 18Po. 1. 5. In the manuscript of Mothes, this height is estimated at 18P°. 7. which would give only 1814 toises, or 3535 metres of absolute elevation, (11,596 feet. Trans.) The great square of the town of Micuipampa, where I found the barometer 18Po. 4. 7, would then be 84 metres (275 feet. Trans.) higher than the level of the streets of Huancavelica. (Recueil d'Observations Astronomiques, vol. i. p. 316.)

12,308 feet. Trans..

mountain 4422 metres. The discovery of the great quicksilver-mine, is generally attributed to the Indian Gonzalo Abincopa or Navimcopa; but it is certain that it goes back to a period long before 1567, since the Incas made use of cinnabar (llimbi) in painting themselves, and procured it from the mountains of Palcas. The working of the mine of the Cerro de Santa Barbara on account of the Crown, began however only in the month of September 1570, nearly the same year in which Fernandez de Velasco introduced the Mexican amalgamation into Peru.

Mercury is found in the environs of the town of Huancavelica, in two very different manners, in beds and in veins. In the great mine of Santa Barbara, the cinnabar is contained in a bed of quartzy sandstone of nearly 400 metres in thickness, and in a direction of hor. 10-11 of the German miner's compass, with an inclina

* 14,506 feet. Trans. This measurement agrees very well with the assertion of Ulloa, who relates that he saw the barometer remain at the bottom of the mine of Hoyo Negro at 17p. 21i. 2; from which we may conclude that the bottom of the mine was then 2159 toises, or 4208 metres of elevation above the level of the ocean (13,805 feet. Trans.) (Ulloa. Noticias Americanas, p. 279.) In this pit then the miners wrought in a point which is 500 metres (1640 feet) higher than the summit of the Peak of Teneriffe. In the Cerro de Hualgayoc, I have seen galleries of which the absolute height exceeded 4050 metres (13,287 feet. Trans.)

tion of 64° towards the west. This sandstone, analogous to that of the environs of Paris, and the mountains of Aroma and Cascas, in Peru, resembles pure quartz. The most part of the specimens which I examined in the geological cabinet of the Baron de Nordenflycht, exhibit very little argillaceous cement. The quartz rock, which contains the mercurial ores, forms a bed in a calcareous breccia, from which it is only separated in its wall and its roof, by a very thin stratum of slate clay (schieferthon), which has been frequently confounded with primitive slate. The breccia is covered with a formation of secondary limestone, and the fragments of compact limestone contained in the breccia, seem to indicate that the whole mass of the mountain of Santa Barbara itself reposes on alpine limestone (alpenkalkstein). This last rock is in fact to be seen on the eastern slope of the mountain near Acobamba and Sillacasa. It is still found at very considerable elevations, and is of a bluish-grey, and traversed by a great number of small veins of calcareous spar. Ulloa observed there in 1761 petrified shells *, at a height of more

*We also found them on the ridge of the Andes, near Montan and Micuipampa; Géographie des Plantes, p. 127. See, as to the marine shells observed at great heights in Europe and America, Faujas de Saint-Fond, Essai de Geologie, t. ii. p. 61-69.

than 4300 metres.* M. de Nordenflycht also discovered pectinites and cardia in a bank of shells, between the villages of Acoria and Acobamba, near Huancavelica, at an elevation surpassing by more than 800 metres t, that of the bank of nummulites found by M. Ramond on the summit of Mont-Perdu.

The cinnabar by no means fills the whole quartz bed of the great mine of Santa Barbara; it forms particular strata; and sometimes it is found in small veins, which drag (se trainent) and unite in masses (stockwerke). Hence the metalliferous mass is only in general from 60 to 70 metres in breadth. Native mercury is extremely rare, but the cinnabar is accompanied with red iron ore, magnetic iron, galena, and pyrites; and the crevices are frequently variegated with sulphate of lime, calcareous spar, and fibrous alum (feder-alaun), with curvilinear parallel fibres. The metalliferous bed at great depths § contains a good deal of orpiment and realgar, or yellow and red sulphurets of arsenic. This mixture formerly occasioned the

§ Particularly below the depth of 230 varas (629 feet. Irans.) The Galena is found nearer the surface of the earth, and even 40 varas lower than the gallery of San Xavier.

death of many workmen, who wrought at the distillation of ores of cinnabar mixed with orpiment, till the government took the resolution of prohibiting the carrying on the works of Cochapata, in which arsenic abounds the most. I suppose that the vapour called umpe, of which the alarming effects are described by Ulloa, is arsenical hydrogen gas; but it has been much more rarely felt than might be believed, from the accounts of the Spanish travellers.

The great mine of Santa Barbara is divided into three stories, (pertinencias) which bear the names of Brocal, Comedio, Cochapata. The depth of the mine is 349 varas; and its total length from north to south 536 varas. It is reckoned that 50 quintals of tolerably rich ores, yield by distillation from 8 to 12 pounds of mercury. The mineral depository is worked by three galleries, viz. the Socabon de Ulloa, the Socabon de San Francisco Xavier, and the Socabon de Nuestra Señora de Belem, begun in 1615, and finished in 1642. The gallery cut by the astronomer Don Antonio Ulloa, who as governor of Huancavelica directed the works for some years, is only 75 varas in length; and its mouth is almost level with the great square of the town. It would require to be still prolonged 2000 varas, to traverse the pertinencia de Cochapata. It is the only gallery which