Of the volcanic groups of the South Sea, the most violent is the farthest east, adjoining the shores of the New World, viz., the archipelago of the Gallipagos, which consists of five considerable islands, very admirably described by Darwin. There are streams of lava down to the very shore of the sea, but no pumice. Some of the trachytic lavas are said to abound with crystals of albite. It is important to examine whether or not this is oligoclase, as on Teneriffe, Popocatepetl, and Chimborazo; or labradorite, as on Etna and Stromboli. Palagonite, exactly similar to that of Iceland or in Italy, was discovered by Bunsen in the specimens of tufa from Chatham Island, one of the Gallipagos. New Holland does not show any signs of recent volcanic activity, except at its most southern point (Australia Felix), at the foot of the Grampian Mountains. N.W. from Port Philip, as also towards the Murray River, there are numbers of volcanic cones and sheets or flows of lava. It would be of great interest and utility to observe the relative inclinations of the Magnetic and the Geographical Equators, by means of the dip of the magnetic needle, though this will be rendered more difficult, from the fact of the ship's course being easterly, that is, contrary, to the Equinoctial current. As regards the low temperature of the current, which I discovered in 1802, running up from 40° S. to the Gallipagos along the coast of South America, and then turning westward, it would be highly important to investigate whether in the eastern part of the South Sea in 7° N. and between 117° and 140° W., there really exists in every season a _counter current_ from west to east. But I need not enlarge upon this topic to such attentive navigators. The line of no inclination was crossed six times by Duperrey between 1822 and 1825. When I first discovered, near Truxillo, the low temperature of the cold Peruvian current, it was 12°·8 Réaumur (60°·8 Fahr.). The temperature observed in the course of twenty years by Mr. Dirckinck von Holmfeld, in the neighbourhood of Callao, expressed in degrees of Réaumur, were as follows:-- September 1802 12°·8 (Fahr. 60°·8) } Thermometer in the air. November " 12°·4 ( " 59°·9) } 13°·3 Réaumur. December, end of 16°·8 ( " 69°·8) } (61°·92 Fahr.) January 1825 12°·7 ( " 60°·57) February " 15°·3 ( " 66°·42) March " 15°·7 ( " 67°·32) April " 14°·5 ( " 64°·62) The temperature of the sea I found to be 22° Réaumur (81°·5 Fah.) north of Cape Blanco, when on my way from Callao de Lima, at which point the cold current diverged towards the Gallipagos.