ERUPTION OF THE HAWAIIAN VOLCANOES. 



587 



from incandescent lavas to the cold or moist strata superincumbent or adjacent. In that 

 case, the hot lavas entering a crevice between cold or moist rocks would originate a series 

 of vibrations which would break open the rock more and more and expose fresh surfaces to 

 the hot lava ; and so on until the heat of the lava has been reduced by conduction to a 

 certain point, when the vibrations cease. If the theory be true that all volcanic eruptions 

 are but the passage of telluric heat into space (our earth's crust being a good non-con- 

 ductor and compelling the passage by certain open ways which are marked by volcanoes), 

 and if this escaping caloric, sometimes compelled to seek one avenue of escape, sometimes 

 another, but when escaping reducing to liquidity all the material of the crust in its way, form- 

 ing what we call lava lakes as in Kilauea, or when less equable, or when, as it were, blocked 

 up or opposed, driving all before it as an eruption or flow of lava, — if this theory be true 

 — and experiments are now being made to throw light upon it — it is not strange that this 

 heat passing through the crust near volcanic vents should act as above supposed. 



The destruction of life and property on Hawaii was comparatively small, owing to the 

 nature of the district affected. The losses were as follows : — 



Lin Ka-u. 



Number of houses destroyed by land-slide 

 Number of houses destroyed by sea-wave 

 Number of houses destroyed by earthquake 

 Number of houses destroyed by lava-stream 



Total 



One life was lost in Puna by the sea-wave, and one in Hilo by a falling cliff. A shock of 

 no greater violence in the city of Boston would probably have killed fifty thousand people, 

 and laid most of the city in ruins. 



The data for determining the direction and force of the vibrations, are quite different 

 from those used by Mallet in his remarkable investigation of the Calabrian earthquake of 

 1857. The houses are mostly of wood and grass, and stone walls are built of angidar blocks 

 of lava, often without any cement ; a brick wall or a wall of hewn stone, is not to be found 

 in Ka-u. On the other hand, the rocks which form the upper crest are of uniform com- 

 position, the direction of the strata is well known, and there are no strata of sedimentary 

 rock to mislead by reflection of earth-waves. On the whole, Hawaii offers many advantages 

 for the study of seismic as well as volcanic phenomena. 



Published March, 1869. 



