LECTURE ON VOLCANOES.

Timaru Herald, Volume LVII, Issue 6066, 27 September 1894, Page 3

LECTURE ON VOLCANOES.

Mr George Hogban, M A., gave a popular leoture on Volcanoes to the Congregational Young People's Union last evening, the Bey Mr Williams presiding over a fair attendance. The leoture was illustrato'l by a number of diagrams and specimens of different kind,* of volcanic produots. Mr Hogben, openod by a reference to the old definition of a volcano as " a burning mountain discharging fire and ashee," and showed that this is correct excapl that a volcano is not practically a mountain, Ihit it does not burn, nor dig*

obarge fire nor ashes. A . volcano is really a hole \n the surface leading to the depths of the earth, and its chief ditohargei are water ia the shape of steam, and molten —burning hot, but not burning— rock. Whence the molten rock and steam, cqmeis still matter of dieoussion. There are four competing theories, dependent upon as many i different views as to the oondition of the earth's interior, viz , (1) the earth is nearly all molten with a thin crust on the outoidq ; (2) it has a thick oiust, and the centre is solid, t but there is a molten belt, or rather shell, a a good distance down ; (8) it is nearly all 1 solid, but there are " pookets " of molten 1 matter which furnish vent and material for ] volcanoes; (4) the earth m wholly solid, but tbe interior is little below melting point and certain natural operators may melt portions of it from time to tim). The majority of vulcaoiato at present prefer the " pocket V < theory. The lecturer thon desoribed the prooees of a volcanio eruption, and took as a typical ex«mplo the building up of Bank's Pen\osu^a, sketching iuocf»site stages ia its formation on, a blackboard. The lava itream frort Mount Horrible, which underlies Timaru, was appropriately referred to. The phenomena of bot springs, and the formation or sinter " terraces " wore also explained. A hearty vote of thanks, was pasted to Mr Hogben on the motion of Mr Bold, and sub. sequently the specimens were examined by many of the audience with much interest. Several songs were sung during the eveniog and the. audience jabted'jq the doxolpgy before tabarating. > .