Some Facts About Volcanoes.

Auckland Star, Volume XVIII, Issue 143, 18 June 1887, Page 1 (Supplement)

Some Facts About Volcanoes.

Mr S. Herbert Cox, F.C.S. 5 F.G.S., instructor in geology, minei'alogy, and mining at the Sydney Technical College, gaTe a lecture in the School of Arts on "Volcanoes."' Mr Cox explained that earlier attempts to study volcanic phenomena had generally been attended with disastrous results to the inquirers, as their investigations had led, them to approach volcanoes when in violent eruption. Later investigations had shown that the immediate cause of all eruptions might be traced to the action of steam. The steam condensed above the mountain and torrents of rain fell, which gave rise to the well-known mud lavas which have done such damage at times, it being probable that Herculaneum was buried under one of these • streams. 'Besides these fragmental ejecta, streams of molten rock are frequently poured out from the craters, and sometimes- flow for great distances; and during' the eruption which took place in Iceland, two streams of lava were poured out from the crater, one of which flowed for 45 and the other 50: miles, entombing 20 villages and filling gorges 200 feet wide and 600 feet deep. A description was given of ,the formation of Monte Nuovo and Graham's Island in- the Mediterranean, both of which had been formed under the eyes of man, and it was stated that in two days Monte Nuovo.reached a height of 440 feet, and after being in eruption for a week became extinct. The lecturer pointed out how difficult it was to say when volcanoes were absolutely ; extinct, for prior to the year 79 Vesuvius had been looked upon as an extinct volcano, and since then it had been known to be dormant for as long as 100 years at a stretch, and Tarawera in New Zealand, which broke into eruption last year, had never been known to be active before,- and had- no sign of a Jjefpre this last eruption commenced, .STtnfwwa