Phillips. — On the Volcanoes of the Pacific. 513 



In the same month —December, 1894 — when I was at Tonga- 

 tabu, the report had come in that Falcon Island had dis- 

 appeared. Keports had previously been made that the island 

 was gradually washing away, the sea being discoloured all 

 around for some five miles owing to the erosion. The Tongaa 

 Government therefore, on the 21st December, sent Mr. Whit- 

 combe down, with Captain John Cassels, Acting Harbour- 

 master, and some other gentlemen, to inquire into the actual 

 state of things at the island. Falcon Island lies about forty- 

 five miles north-north-west of Nukualofa, in longitude 175° 20'. 

 Captain Cassels and a Mr. O'Connor swam through the 

 surf, which there swarmed with small sharks. They found 

 the island to be "cold, steep, water of 20 fathoms all round, 

 about a mile and a quarter in diameter, and three and a half 

 in circumference. At the southern end about 50 ft. high ; in 

 the centre a fresh- water mineral lake about 4 ft. to 5 ft. deep, 

 with a solid-rock bottom. In places very hot to the feet, as 

 Mr. O'Connor found." They had to take their boots off when 

 swimming from the boat, which lay outside the surf. The 

 island itself was a mass of red and black scoria, whose 

 gradual washing-away caused the discolouration of the sur- 

 rounding sea. I have given Captain Cassels's own words con- 

 cerning his visit. I also present to our Museum specimens of 

 the red and black scoria, and of the solid-rock bottom of the 

 lake, which Captain Cassels tied up in his shirt when swim- 

 ming back to the boat. The formation of the scoria is 

 remarkable. The little spheres and oblates, if water-worn, 

 must have been so formed by submarine action, as there was 

 no active volcano on the island, and little vegetation, so far as 

 I could make out. The black scoria is partly composed of the 

 little hollow bombs, somewhat similar, I believe, to those 

 thrown out in the great eruption of Tarawera in June, 1886, 

 and at other times before and since. The formation of these 

 little bombs is no doubt easily explained. But in Miss 

 Bird's account of the great eruption of Mauna Loa, Sand- 

 wich Islands, in 1868, the volcanic phenomena there dis- 

 played forces m nature of which we know little or nothing. 

 The motion of the land during the eruption was " vertical, 

 rotary, lateral, and undulating"; mountains fell and split up 

 in all directions ; the surging of the imprisoned lava was heard 

 through the ground ; its flow of twenty miles underground ; 

 its bursting through the soil in huge fountains, rotating 

 towards the south ; "in the air both lava and stones always 

 rotated towards the south." 



It will be noticed, too, that the black scoria gravel is much 



smaller than the brown gravel ; but this may be only a small 



local difference in the strata. I am well aware that the lava 



from different volcanoes is different. The solid-rock bottom 



33 



