VULCANISM.

Timaru Herald, Volume XIIC, Issue 13685, 29 August 1908, Page 3

VULCANISM.

Mr E.. K. Mulgan, M.A. Inspector oj Schools,.Christchurch, gave an interesting lecture in Trinity ; Hall last evening on " Vutcanism," a term applied to the totality of volcanic activities. There, was a fair . attendance, largely composed of teachers (as was desired) and a number of High School boys were present. Some of the teachers cama long distances —from Willowbridge and Waihaorunga southward, Clandeboye and Woodbury northward, and Pleasant Point and Opihi westward. Mr Hardy managed a lantern for the display of a considerable number of instructive views, the exercise of ears and eyes together making the lecture more than doubly interesting. Mr Mulgan, who was introduced by Mr A. Bell, commenced by pointing out that the theory that children should not be taught anything in geography that they could not be shown would do the children great wrong. That woidd debar inland pupils from learning anything about the sea, which was obviously absurd; and the same conclusion applied to the tabooing of instruction about glaciers or volcanoes because there did not happen to be one in the neighbourhood. He then proceeded to discuss the ascertained facte regarding the temperature of the earth's interior and the theories that had been advanced to explain those facts. The. compulsory shrinkage of the exterior, which had resulted in the crumpling up of mountains was next dealt with, and the explanations that had been offered and had found provisional acceptance; The lantern was then brought into play, the theory of geysers explained with the aid of a diagram,, and photos of a number of those in the North Island were shown, a theory of "soaping" stated, and the formation of sinter explained. Turning to volcanoes, explosive eruptions, emissions of, lava, the formation, of different classes of cones by .different materials, and tha

formation of dykes and necks or plugs were explained by -reference•', to diagrams and numerous photographs'from New Zealand's volcanic fields, active and extinct, including the Port Hills. Mr Mulgan brought with him some small volcanic " bombs" picked up 'at Auckland, and some dust "he picked up from his verandah at Tauranga, where it fell from the eruption of Tarawera, 50 miles away, in 1886. Tile, morning, he said, became absoluVely dark, and some people thought the world was coming to an end.' The noises'of the eruption were .not heard at Tauranga, though they were, heard at much greater distances in other directions. One,of the finest pictures shown, it may be mentioned, was a view of a huge sunlit steam cloud rising from' a hot lake in White Island, Bay of Plenty. , The origin oE volcanoes, in the origin of the molten materials and the mechanism of their extrusion formed another interesting section of the explanatory portion of the lecture, and in related. to this came in the theories of crust-folding in mountains and the relation of volcanic lines and centres to great, areas of depression (the oceans), and' of uplift (the continents) the greatest volcanic activity to-day being found where pairs of areas of uplift and depression mst together. In connection with mountain uplift the interesting facts wet>e mentioned that the rocks in the European Alps occupy less space by 76 miles than they did before being squeezed together, and the Appalacians 46 miles less, and the difficulty of fitting these great compressions: into any theory of contraction by cooling was pointed out. The lecture was listened to with the greatest attention, stated in simple language, and Mr Valentine's motion for a-vote-of thanks was carried by acclamation. A number of those present remained to ' inspect - the samples Mr Mulgan had . brought with him.