500 Transactions. — Geology. 



hour's walking distance from and beneath Ketetahi. That 

 day Te Mari was steaming less than it had done on the 

 previous days, and scarcely more than Ketetahi ; but the 

 slightly bluish colour of its steam betrayed a somewhat higher 

 temperature. But for this fact one might have thought the 

 period of activity was almost at an end, and I little hoped 

 that I should witness one of those eruptions of which I had 

 so often heard or read. We were sleeping quietly in 

 our camp when, at about half-past 12 o'clock, we were 

 awakened by a thundering noise, and on going out of our 

 tent we beheld a very remarkable spectacle — indeed, I after- 

 wards heard that at Otakou the natives had already com- 

 menced leaving, and would have left altogether but for the 

 short duration of the violent phase of the outbreak. 



Against the starlit and cloudless sky stood a gigantic 

 pillar of ash-bearing steam, broadening towards its summit, 

 and overtopped by a detached roundish mass of the same 

 appearance. Evidently the explosion had begun by a single 

 shot, followed by a rest of some seconds. The pillar of steam 

 — as ash-bearing and other volcanic clouds always are, as 

 long as they are in ascending movement, hotter than the 

 surrounding air — was of an exquisite cumulus character. This 

 and its absolute opaqueness and dark colour gave it a strange 

 appearance, almost like that of a solid body — an enormous 

 stalagmite, as it were. But the most surprising sight was 

 the wonderful display of diiiferent kinds of light phenomena. 

 Whereas at no time had I seen the slightest fire - reflec- 

 tion above Te Mari, the lower parts of the steam column 

 were now all aglow with a dark-red glare. A large number 

 of what looked like bright sparks shot high up, and fell down 

 in parabolic lines. There was going on, besides, a continuous 

 play of electric lightning in the clouds, mostly, but not always, 

 in the lower parts. I think there was on the average fully 

 one lightning flash to the second. These lightning flashes did 

 not differ from ordinary flashes except that they were mostly 

 rather short ; their being confined to one spot of the sky, and 

 their wonderful frequency, made, too, a very curious impres- 

 sion. The thunder blended together and formed a continuous 

 roar, which, however, at our station was not deafening. 

 But the most remarkable and interesting phenomenon had 

 yet to come. The upshooting sparks (here I describe the 

 immediate impression only, giving the explanation later on) 

 by degrees became rarer, and the lightning also; and then 

 there appeared large flames of a brilliant- blue hue, which 

 mingled with the ascending steam — apparently floating, as it 

 were, free in the air at some distance above the mouth of the 

 crater. I estimated the height of the flames at about 100 ft. 



About a quarter of an hour after its commencement the 



