TRUE VOLCANOES. 369 



cope at the summit of the volcano, but nothing is ever said 

 of perpetual snow.(*) I have already observed, in a former 

 part of this work, that the Mouna Loa (13,758 feet) and the 

 Mouna Kea (13,950 feet) are respectively more than 1000 and 

 821 feet lower than the lowest limit of perpetual snow, as 

 found by me in the continental mountains of Mexico under 

 19^° latitude. On a small island the line of perpetual snow 

 should lie somewhat lower, on account of the less elevated 

 temperature of the lower strata of air in the hottest season 

 of the tropical zone, and on account of the greater quantity 

 of water held in solution in the upper atmosphere. 



The volcanoes of Tafoa* and Amargura* in the Tonga 

 group are both active, and the latter had a considerable erup- 

 tion of lava on the 9th of July, 1847. f It is extremely re- 

 markable, and is in entire accordance with the stories of the 

 coral animals avoiding the shores of volcanoes, either at the 

 time or shortly before, in a state of ignition, that the Tonga 

 islands of Tafoa and the cone of Kao, which abound in coral 

 reefs, are entirely destitute of those creatures. J 



Next follow the volcanoes of Tanna* and Ambrym,* the 

 latter westward of Mallicollo, in the Archipelago of the New 

 Hebrides. The volcano of Tanna, first described by Eeinhold 

 Forster, was found in a full state of eruption on Cook's dis- 

 covery of the island in 1774. It has since remained con- 

 stantly active. Its height being only 458 feet, it is one of 

 the lowest fire-emitting cones, along with the volcano of 

 Mendana, hereafter to be noticed, and the Japanese volcano 

 of Kosima. There is a great quantity of pumice on Mal- 

 licollo. 



Matthew's Rock,* a very small smoking rock island, about 

 1183 feet high, the eruption of which was* observed by D'Ur- 

 ville in January, 1828. It lies eastward of the southern 

 point of New Caledonia. 



The volcano of Tinakoro,* in the group of Vanikoro or 

 Santa Cruz. 



In the same Archipelago of Santa Cruz, fully 80 geograph- 

 ical miles N.N.W. of Tinakoro, the volcano* seen by Men- 

 dana so early as 1595 rises out of the sea to a height of about 

 213 feet (lat. 10° 23' S.). Its eruptions have sometimes 



(*) Wilkes, p. 114, 140, and 157 ; Dana, p. 221. From the perpetu- 

 al transmutation of the r and I, Mauna Loa, is often written Roa, and 

 Kilauea, Kirauea. t Dana, p. 25 and 138. 



X Dana, Geology of the United States Exploring Exped., p. 138. (See 

 Darwin, Structure of Coral Reefs, p. GO.) 



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