Bibliography.—S. Berthelot, Antiquités canariennes (Paris, 1839); Baker Webb and S. Berthelot, Histoire naturelle des îles Canaries (Paris, 1839); Paul Broca, Revue d’anthropologie, iv. (1874); General L. L. C. Faidherbe, Quelque mots sur l’ethnologie de l’archipel canarien (Paris, 1875); Chil y Naranjo, Estudios historicos, climatologicos y Patologicos de las Islas Canarias (Las Palmas, 1876-1889); “De la pluralité des races humaines de l’archipel canarien,” Bull. Soc. Anthrop. Paris, 1878; “Habitations et sépultures des anciens habitants des îles Canaries,” Revue d’anthrop., 1879; R. Verneau, “Sur les Sémites aux îles Canaries,” and “Sur les anciens habitants de la Isleta, Grande Canarie,” Bull. Soc. Anthrop. Paris, 1881; Rapport sur une mission scientifique dans l’archipel canarien (Paris, 1887); Cinq années de séjour aux îles Canaries (Paris, 1891); H. Meyer, Die Insel Tenerife (Leipzig, 1896), “Über die Urbewohner der canarischen Inseln,” in Adolf Bastian Festschrift (Berlin, 1896); F. von Luschan, Anhang über eine Schädelsammlung von den canarischen Inseln; R. Virchow, “Schädel mit Carionecrosis der Sagittalgegend,” Verhandlungen der Berliner Anthrop. Gesellschaft (1896); G. Sergi, The Mediterranean Race (London, 1901); The Guanches of Tenerife ..., by Alonso de Espinosa, translated by Sir Clements Markham, with bibliography (Hakluyt Society, 1907).
GUANIDINE, CN3H5 or HN:C(NH2)2, the amidine of amidocarbonic acid. It occurs in beet juice. It was first prepared in 1861 by A. Strecker, who oxidized guanine with hydrochloric acid and potassium chlorate. It may be obtained synthetically by the action of ammonium iodide on cyanamide, CN·NH2 + NH4I = CN3H5·HI·; by heating ortho-carbonic esters with ammonia to 150° C.; but best by heating ammonium thiocyanate to 180°-190° C., when the thiourea first formed is converted into guanidine thiocyanate, 2CS(NH2)2 = HN:C(NH2)2·HCNS + H2S. It is a colourless crystalline solid, readily soluble in water and alcohol; it deliquesces on exposure to air. It has strong basic properties, absorbs carbon dioxide readily, and forms well-defined crystalline salts. Baryta water hydrolyses it to urea. By direct union with glycocoll acid, it yields glycocyamine, NH2·(HN):C·NH·CH2·CO2H, whilst with methyl glycocoll (sarcosine) it forms creatine, NH2·(NH):C·N(CH3)·CH2·CO2H.
Many derivatives of guanidine were obtained by J. Thiele (Ann., 1892, 270, p. 1; 1893, 273, p. 133; Ber., 1893, 26, pp. 2598, 2645). By the action of nitric acid on guanidine in the presence of sulphuric acid, nitroguanidine, HN:C(NH2)·NH·NO2 (a substance possessing acid properties) is obtained; from which, by reduction with zinc dust, amidoguanidine, HN:C(NH2)·NH·NH2, is formed. This amidoguanidine decomposes on hydrolysis with the formation of semicarbazide, NH2·CO·NH·NH2, which, in its turn, breaks down into carbon dioxide, ammonia and hydrazine. Amidoguanidine is a body of hydrazine type, for it reduces gold and silver salts and yields a benzylidine derivative. On oxidation with potassium permanganate, it gives azodicarbondiamidine nitrate, NH2·(HN):C·N:N·C:(NH)·NH2·2HNO3, which, when reduced by sulphuretted hydrogen, is converted into the corresponding hydrazodicarbondiamidine, NH2·(HN):C·NH·NH·C:(NH)·NH2. By the action of nitrous acid on a nitric acid solution of amidoguanidine, diazoguanidine nitrate, NH2·(HN):C·NH·N2·NO3, is obtained. This diazo compound is decomposed by caustic alkalis with the formation of cyanamide and hydrazoic acid, CH4N5·NO3 = N3H + CN·NH2 + HNO3, whilst acetates and carbonates convert it into amidotetrazotic acid,
Amidotetrazotic acid yields addition compounds with amines, and by the further action of nitrous acid yields a very explosive derivative, diazotetrazol, CN6. By fusing guanidine with urea, dicyandiamidine H2N·(HN):C·NH·CO·NH2, is formed.
GUANO (a Spanish word from the Peruvian huanu, dung), the excrement of birds, found as large deposits on certain islands off the coast of Peru, and on others situated in the Southern ocean and off the west coast of Africa. The large proportions of phosphorus in the form of phosphates and of nitrogen as ammonium oxalate and urate renders it a valuable fertilizer. Bat’s guano, composed of the excrement of bats, is found in certain caves in New Zealand and elsewhere; it is similar in composition to Peruvian guano. (See [Manures and Manuring].)
GUANTA, a port on the Caribbean coast of the state of Bermúdez, Venezuela, 12 m. N.E. of Barcelona, with which it is connected by rail. It dates from the completion of the railway to the coal mines of Naricual and Capiricual nearly 12 m. beyond Barcelona, and was created for the shipment of coal. The harbour is horseshoe-shaped, with its entrance, 1998 ft. wide, protected by an island less than 1 m. off the shore. The entrance is easy and safe, and the harbour affords secure anchorage for large vessels, with deep water alongside the iron railway wharf. These advantages have made Guanta the best port on this part of the coast, and the trade of Barcelona and that of a large inland district have been transferred to it. A prominent feature in its trade is the shipment of live cattle. Among its exports are sugar, coffee, cacáo, tobacco and fruit.