hy Alexander von Ilumholdt. xxxi 



wlietlier or not this is oligoclasc, as on Teneriffc, Popo- 

 catepetl, and Chimborazo ; or labradorite, as on Etna and 

 Stromboli. Palagonite, exactly similar to that of Iceland or 

 in Italy, was discovered by Bnnscn 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 schists of lava. 



It would be of great interest and utihty 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, 



