Finally, any attempt to load vessels without the proper licences, would subject them to be seized by the Government vessels appointed to cruise off, and visit the different guano deposits, in order to prevent not only the illegal extraction of guano by foreign trading vessels, but also to prevent the natives of Peru from violating the Government orders against visiting those localities, and destroying or disturbing the birds. Notwithstanding this cuts off the free trade in the article, it goes to show what we have always endeavored to impress upon the minds of American farmers, that the supply is inexhaustible--at least in this age and generation--and as every one grows wiser and wiser, it is probable the next will have no occasion to use such an old fashioned article as bird dung for manure. During the present, however, our advice is to every person occupying land which needs something to improve its fertility, to use guano--genuine Peruvian guano--purchased of reliable merchants--and the fewer the better between the importer and consumer. _The Quantity inexhaustible._--By those surveys, the quantity was ascertained to be upwards of TWENTY MILLIONS OF TONS. As this must appear so enormous as to be almost incredible, we present the annexed cut, supposed to represent a vertical section of one of the Chincha islands and the depth of the deposit according to the government surveys. The paralel lines at the bottom represent the level of the water--the crooked line above, the surface of the rock; its position having been ascertained by boring and observations of the surveyors. The rounded line is the surface of the island as it now appears; all between that and the rock being guano. The almost perpendicular line at the left hand, 100 feet high, is the rock at which ships lay to take in cargo. The space under the dotted line show a comparison of the quantity taken away, as it relates to the whole upon the island. The well hole represented in that section was dug some fifty feet deep to prove the guano was of equal quality at the bottom. The Chincha Islands are three in number; not remote from each other or differing very materially in size or general feature. The Geological formation presents the appearance of masses of rock jutting out above the surface of the ocean--and occasionally rising nearly perpendicularly to a height of from 50 to 100 feet. At a distance, the islands present to the eye a somewhat conical form; owing probably to the greater deposits of guano in the centre; and all appear equally rich in quantity and quality. The "North Island" is estimated to be about 300 feet at its greatest elevation; it is about 1-1/2 miles in length, and from 1/2 to 3/4 of a mile average width. In sailing round them, the guano appears to many places to extend to the water's edge. [Illustration: SECTIONAL VIEW OF THE NORTH CHINCHA ISLAND.]