Page:Encyclopædia Britannica, Ninth Edition, v. 11.djvu/245

Rh ties in which to die, as appears from the great heaps of bones bearing no sign of having been gnawed by the puma, which have been found in particular spots.  GUANAJUATO, or, a city of Mexico, capital of the state of Guanajuato, is situated in 21° 0' 50” N. lat. and 100° 54’ 27” W. Jong., at a height of 7200 feet above the sea. Built as it is at the meeting- place of three mountain gorges, and obliged by lack of space to climb the underfalls of the surrounding heights, Guanajuato has a highly picturesque appearance. The houses of the lower town are four or five stories in height, most of the streets are narrow and tortuous, and the priu- cipal is small though beautiful. The cathedral, the Jesuit church, the mint dating from 1812, the new theatre built in 1874, the university, and the gymnasium are worthy of mention. The Alhondiga de Granaditas, originally a corn magazine, was occupied as a fort in the War of Independ- ence, and acquired peculiar interest as the spot where the patriot Hidalgo met his death. Guanajuato, founded in, owed its existence and prosperity to the fact that it is the centre of the greatest silver-mining district in the world. Of the individual mines perhaps the most famous is the Valenciana, with a shaft 2000 feet deep, which is in process of being cleared of the water by which it has long been flooded. The population, which includes a consider- able number of foreigners, formerly amounted to 100,000, but in 1869 was only 63,500.  GUANCAVELICA. See.  GUANO. The deposits of guano, or huano, known locally as Awaneras, are found in characteristic condition and abundance upon a large number of the islands lying off Peru and upon certain parts of the mainland. They occur in Bolivia and to the north of Peru also, but are there generally poorer in quality, if not always less in quantity. For the production and preservation of good guano twoconditions are requisite—a rainless or nearly rainless climate and abund- ance of fish in the waters of the ocean. Both conditions are fulfilled on parts of the Bolivian and Peruvian coasts. The penguins, gannets, divers, cranes, cormorants, flamingoes, and other fish-cating birds thus find ample supplies of food ; while their excreta retain their soluble and more valuable constituents. But even Peruvian guano is not exclusively excrementitious, nor wholly tlie produce of birds. These marine aud maritime huaneras are the breeding-places, the resorts, and the cemeteries not only of sea-birds, but of many other sea-animals,—seals, sea-lions, &c., frequenting many guano lands and islands, and adding considerably during life and when dead to the deposits. In Peruvian guano, it is true, the evidences of its origin are often obscure, but the somewhat complex sources of this material are well shown in the West-African guano islands, On these Mr T. R. E:len found (1845) three varieties of guano, the lowest being a crust or rock guano, the next above this being a seal guano, containing much seal-fur, and the uppermost layer being a bird guano, in which there were many mum- mified bird skins and large quantities of feathers. The dung of bats, which has been found in large quantities in many caverns, both in Europe and in certain parts of France, the Pyrenees and Italy, in New Zealand, and on the North American continent, has been designated “bat-guano.” Further, the term guano, even when employed to describe the marine and maritime deposits previously mentioned, includes a considerable variety of substances very different in chemical composition and in manure value. For the deposits of guano occurring on the rainless or nearly rainless islands and coasts of Peru vary much in the proportion of their constituents—such variation being due less to differences in the origin of the deposits than to subsequent changes. Exposure to the action of the sea and of sea-mist, and the pressure of superincumbent layers, are not without influence on the nature of the guano, very different qualities being found at different depths. Although allusions to guano occur in the writings of travellers in the and 18th centuries, the credit of directing the attention of Europe to this curious and use- ful product is due to Humboldt. In 1804 he brought from the Chincha Islands a specimen which Klaproth and then Fourcroy and Vauquelin analysed. But it was not until the publication in 1840 of Liebig’s work on chemistry in its relations to agriculture and physiology had demonstrated the importance of artificial manures that a lively interest in this Peruvian fertilizer was awakened. In that year a firm of merchants of Lima sent a large cargo of guano to England; but it was not until 1842 that the regular trade in guano began. Messrs Gibbs & Co. imported 182 tons in that year, while in 1862 the amount was no less than 435,000 tons. The price was lowest (£9 per ton) in 1848-9. It rose successively, in the years 1854 to 1856, from £10 to £13, and has since remained at about the last sum for the best qualities. Happily the Peruvian Guano Company are now permitted to sell this manure according to the results of analysis, and not, as before, at a fixed price irrespective of the variable qualities of different cargoes. Each unit per cent. of nitrogen is set down as worth 19s, 2d. per ton; while the phosphates, calculated as tricalcic phosphate, are reckoned as worth 2°. 34$d. per unit per ton. The only drawback to this plan lies in the rather exaggerated price which it assigns to the low qualities of Peruvian guano, namely, those which are poor in nitrogen but rich in phosphates—containing perhaps 40 to 60 per cent. of these compounds, which may be much more cheaply purchased in other forms. Still it must be urged that the phosphates of Peruvian guano are more useful than those from most other sources, on account of their physical condition, and their sulubility. After all, however, the high phosphatic guanos are not much appreciated by farmers, who prefer to use bones and supcr- phosphates as manure for grass lands and root crops. For a long time the group of Peruvian islands known as the Chinchas furnished nearly all the guano that found its way to Europe. When these deposits, amounting to 7 million tons or more, were practically exhausted,—only 150,000 tons of deep deposits remaining in 1872,—their further working was stopped except for use in Peru it: elf. Then the guanos on the Macabi and Huanape islands weie exported to Europe, in four years (1870 to 1874) about 1 million tons having been shipped and about half a million tons remaining in 1875. Since then the Lobos islands, situated about 70 miles north of Macabi, have been worked, as have also the islands of the Ballestas group. Even in 1871 three-fourths of the cargoes of nitrogenous guano were from Huanape, but the amount of nitrogen generally present in them was rather low, often not exceeding 19 per cent. of “potential” ammonia, while the percentage of water was remarkably high—sometimes not less than 25 per cent. The Ballestas guanos of the same year were drier and contained one-third more nitrogen. In spite of many testings and surveys, the amount of Peruvian guano still remaining to be exported has not been even approximately determined. Not only do contiguous deposits differ much in composition, but it is frequently impossible to ascertain what is guano and what is sand or rock. Sometimes the layers of guano are too thin to be worth removing, in other places they fill up ravines toa much greater depth than would be imagined. An estimate of the total quantity of Peruvian guano remaining in 1877 