GUANO. This valuable manure is the excrement of sea- fowl, and appears to have been used as a manure long before Pera was visited by the Spaniards. A recent German traveller, Meyer, says, 'Along almost the whole coast of Peru this excrementitious matter covers the small islands and cliffs near the coast, and on some spots lies in such enormous beds as could only be produced by the accumulation of thousands of years.' About the commencement of 1843 guano was discovered on the island of Ichaboe, about two miles and a half from the main land of Africa, in 13' S. let., and 15' E. long. The place soon attracted notice, and by the end of 1811 the whole of the guano had been carried away. As many as 350 ships have been anchored off the island at the same time. The guano was from 35 to 38 feet in depth, and the deposit extended to a length of about 1100 feet, with an average width of 400 feet. Towards the close of 1844 another guano island (Malagas) was discovered at the en trance of Saldanba Bay. The guano covers an extent of about eight miles, and the thick ness is from about four yards to eight yards. It has been supposed that the excrement of the sea-fowl which swarm on some parts of the coast of Great Britain might be used as a fertiliser with the same results as Peruvian or African guano ; but the quantity which could be collected is comparatively small, as the animal accumulation is in most cases washed away by the rains, and the valuable properties of that which remains are dissipated by the changeable nature of our climate.
The value of guano is to be estimated ac cording to the proportions which it contains of-1, ammonia; 2, phosphates ; 3, organic matter. African guano has the largest pro portion of soluble matter, and that from Peru is remarkable for the quantity of luric acid that it contains, an element which dissolves very slowly. It is said that 4 cwts. of guano, which is the usual quantity applied to one acre, are equal in effect to fifteen tons of farm yard dung. It is usually mixed with pulverised earth to prevent it from coming in contact with the seeds. For small allotments or gar dens it is often most convenient to use guano in a liquid state, in which case &lbs. of guano may be mixed with twelve gallons of water, and used after it has stood twelve hours, and the proportion per acre may be from a half to one cwt. of guano to 160 gallons of water.
The quantity of guano imported in the last four years has been very considerable:— 1847 82,134 tons.
1848 .. 71,414 „ 1849 .. 83,438 „ 1850 .. 116,926 „