Guano
2 of the 7 encyclopedias on this shelf carry an entry for Guano. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
a grayish-white, yellowish, dark brown, or reddish substance. It is a bone phosphate of lime or osteolite with some impurities. Found in islands off the Peruvian and other South American coasts, also in those off the coast of Africa and elsewhere. Guano from different localities has been differently named. It has been called pyroclasite, pyroguanite, sombrerite, and glaubapatite. Guano is formed by the droppings of multitudinous birds, in secluded places where they have been undisturbed for ages. GUÁNTÁNAMO (gwän-tän-ä'mō) BAY, a harbor of southern Cuba, 38 miles E. of Santiago. To the right of the entrance is a range of rocky hills; on the left the shore is low and swampy. It was just outside of this bay that United States war vessels, during the early part of the war with Spain, tried to cut the cables which extended from Santiago to Guantánamo and thence to Spain. On May 18, 1898, the "St. Louis" and the tug "Wampatuck" endeavored to get into the mouth of the harbor, but the Spanish batteries and a gunboat in the bay opened such a severe fire that the "Wampatuck" was forced to withdraw, after grappling a cable about 800 yards from the shore. On June 10, the United States cruiser "Marblehead" shelled the hills on the right of the bay where the enemy had erected earthworks, and the next day the transport "Panther" landed 600 marines at Cai manera, Cuba. In July, 1901, Guantánamo Bay was selected by the United States Government as the site of one of four projected naval stations on the Cuban coast. The construction was completed in 1916. Pop. of district about 51,100. GUAPORÉ (gwä-pō-rā'), a river of South America, rises in Brazil, and for some distance forms the boundary bethe Mamore to form the Madeira. GUARDAFUI (gwär-dä-fwē') CAPE, the extreme E. point of the African continent, and the extremity of an immense promontory, the Somali country, stretching seaward in an E. N. E. direction, and washed on the N. W. by the Gulf of Aden and on the S. E. by the Indian Ocean.
Aiton's Encyclopedia (1910)
gwa'no, the excrement of birds. Commercial guano, used by gardeners for a fertilizer, is imported in sacks from rainless islands off the west coast of South America . On account of penguins, gannets, and other birds, immense amounts of guano have accumulated. Humboldt in his travels, 1804, was the first to call attention to the chance of making money by its sale, and its desirability as a fertilizer for land. One ton of guano is considered equal to thirty-four tons of barnyard manure. One small group of low rocks off the coast of Peru is reported to have yielded 14,000,000 tons of guano, valued at $840,000,000, before the supply was exhausted. Both Chile and Peru have derived large sums of money from these deposits, but they are now about at an end. To realize their magnitude, we have only to recall that these comparatively small tracts were used as breeding grounds for centuries by millions of birds larger than geese, and that no rain fell to carry the guano away. The Germans have found a supply on the coast of German Southwest Africa. See Peru ; Fertilizers