tTKAVEKS. — On the Causes of Volcanic Eruptions, 88l 



had formed ; but by stamping with our heels this was easily 

 broken through. After reaching the saddle, or " col,'' we 

 descended by the great snow-field between the south-east peak 

 facing Karioi and the main peak, which we were unable to 

 ascend in the morning on account of its frozen surface. This 

 field reaches down to 6,000 feet, and is traversed by numerous 

 crevasses ; but these were successively avoided, and in little 

 more than half an hour we reached the lowest limits of the 

 snow. In descending the field " glissading " was resorted to, as 

 on account of the steepness this rapid mode of progression was 

 found to be the easiest and safest. 



A rough, difficult walk of two hours, over a tumbled and con- 

 fused mass of rocks brought us back to our camp. 



For several days afterwards Mr. Dunnage and Dalin suffered 

 severely from snow-blindness, the fierce glare of the sun on the 

 ghstening snow having induced acute inflammation of the eyes. 



Aet. XLII. — Notes in reference to the Prime Causes of the 

 Phenoviena of Earthquakes and Volcanoes. 



By W. T. L. Teavees. 

 [Eead before the Wellington Philosophical Society, 25th August, 1886.] 



The recent outburst of volcanic activity in the Lake District 

 naturally excites our curiosity in relation to the prime cause of 

 earthquakes and volcanic phenomena ; and I i^ropose, in this 

 paper, to call attention to some points which appear to me mate- 

 rially to affect the solution of this question, but which are not 

 referred to, so far as I have been able to ascertain, in any geo- 

 logical works. In order, however, that the bearing of the 

 matters to which I am about to call attention may be under- 

 stood, it is necessary that I should refer, in the first place, to 

 the speculations of astronomers and physicists respecting the 

 original condition of our globe as a concrete mass, because, if 

 those speculations be well founded, it is clear that the pheno- 

 mena of earthquakes and volcanoes must be associated with the 

 continued existence of fused matter at no great depth below its 

 surface. 



Herschel long ago pointed out how, under the action of gravi- 

 tation, cosmical matter "so diffused as to be scarcely discern- 

 ible " might be condensed into a comparatively small mass. 

 Kant, in his " Naturgeschichte, des Himmels," (published in 

 1765,) assumed that all the materials composing the spheres that 



