GUANO or HUANO. A substance first noticed by Humboldt and sent by him from Peru to France, where it was ex amined by Vauquelin. It is the excre ment of sea-birds inhabiting the coast of South Seas. Besides excrement, it is made up of the remains of penguins, albatrosses, and gannntts, booby birds and seals. It is found at Chincha and Payta, in Peru, and in Chili. It also abounds in Iehaboe and a few smaller islands off the West coast of Africa. Peruvian guano is found on the islands of the Pacific, near the coast of Peru, and some of the head lands on the adjacent shores between lat. 13° and 21° South. It is here deposited to the depth of 50 and 60 feet. Within this district rain seldom falls, and there is little waste either of the substance or quality of these accumulations from the ispse of time or the action of elements. The water fowl, which resort to this coast and the vicinal island, subsist principally on fish, and their faces are, of course, richer in nitrogen than any species of the feathered tribes, excepting such as are exclusively carnivorous.
The Chincha islands, which afford the best Peruvian guano, are three in num ber, and lie in one line from north to south, about half a mile apart. Each is land is from five to six miles in circum ference, and consists of granite covered with guano in some places to a height of 200 feet, in successive horizontal strata, each stratum being from 8 to 10 inches thick, and varying in color from light to dark brown. No earthly matter whatever is mixed with this vast mass of excre ment. At Mr. Bland's visit to these is lands in 1842, he observed a perpendicu lar surface of upward of 100 feet of per fectly uniform aspect from top to bottom. In some parts of these islands, however, the deposit does not exceed 3 or 4 feet in thickness. In several places, where the surface of the guano is 100 feet or more above the level of the sea, it is strewed here and there with masses of granite, like those from the Alpine mountains, which are met with on the slopes of the Jura chain. These seem to indicate an ancient formation for the guano, and ter raqueons convulsions since that period. No such granite masses are found imbed ded within the guano, but only skeletons of birds.
The good preservation of the Chincha guano is to be ascribed to the absence of rain ; which rarely, if ever, falls between the latitude of 14° south, where these is lands lie, about 10 miles from the main land, and the latitude of Paquica, on the island of Bolivia, in 21° S. L. By far the soundest cargoes of guano which have been analyzed have come from Chincha and Bolivia. Beyond these limits of latitude, where rain falls in greater or less abun dance, the guano is of less value—and what has been imparted from Chili has been found very far advanced in decay —most of the ammonia and azotized ani mal substances having been decomposed by moistnre, and dissipated in the air (by the eremacausis of Licbig), leaving phos phate of lime largely to predominate along with effete organic matter. The range of
the American coast from which the guano is taken must therefore be well consider ed; and should not extend much beyond the Chincha islands as the northern limit, and Paquica, in Bolivia, as the southern.
Peruvian guano is of a light brown co lor, resembling yellow loam, and is the best guano yet discovered, or than any other manure yet known ; besides nitro gen, which it contains so abundantly, it contains a large amount of phosphoric acid united with lime and magnesia, and as both of these substances are so neces sary to the cultivated crops, it is the rea son why this substance is the manure. The following remarks of Dr. Ure ex plain this point more fully :— The admirable researches of Professor Liebig have demonstrated that AZOTE, the indispensable element of the nourish ment of plants, and especially of wheat and others abounding in gluten (an azo tized product), must be presented to them in the state of ammonia, yet not altoge ther ammonia in the pure or saline form, for, as such, it is too readily evaporated or washed away ; but in the dormant, or as one may say, in the potential condition in contradistinction from the actual. Genuine Peruvian and Bolivian guanos, like those which have been minutely ana lyzed, surpass very far all other species of manure, whether natural or artificial, in the quantity of potential ammonia, and, therefore, in the permanency of their no tion upon the roots of plants, while, in consequence of the ample store of actual ammonia which they contain ready form ed, they are qualified to give immediate vigor to vegetation. Urate of ammonia constitutes a considerable portion of the azotized organic matter in well-preserved guano ; it is nearly insoluble in water, not at all volatile, and is capable of yield ing to the soil, by its slow decomposition, nearly one-third of its weight of ammonia. No other manure can rival this animal sa line compound. One of the said samples of guano afforded me no less than 17 per cent. of potential ammonia, besides 41 per cent. of the actual or ready formed ; others from 7 to 8 per cent, of ammonia in each of these states respectively. These guanos which were examined are the mere excrement of birds, and are quite free from the sand, earth, clay, and common salt, reported in the analyses of some guanos, and one of which (sand) to the amount of 30 per cent. has been found in a sample of guano from Chile.