Malfeoy. — On Geyser-action at Botorua. 583 



attributed to outside or surface influence. I noticed that 

 when Pohutu was in eruption Waikoroihi would stop, and 

 vice versa. This showed that they were hydrostaticahy con- 

 nected, and, as long as Waikoroihi played, the water ejected, 

 finding its way into the Blue Pool of Pohutu (E, Te Horo) at a 

 considerably-reduced temperature (about 160° Fahr.), would so 

 cool the water in the Blue Pool that it would not boil up whilst 

 ,this lasted. As it did not cause the water to rise in that pool, 

 I concluded that it might find its way back into Waikoroihi, 

 and thus be thrown up again and again. I tested this by 

 discolouring the water in the Blue Pool with loam, and found 

 that, though the small bits of grass, moss, &c., were not re- 

 ejected, the water from Waikoroihi was to some extent dis- 

 coloured. 



Taking the opportunity of a visit of the Hon. Mr. Mitchel- 

 son, the late Minister for Public Works, to our district, I 

 explained my views on these matters to him, with an 

 imaginary sketch of the geyser-tubes. Mr. Mitchelson took 

 considerable interest in it, and authorised my making some 

 experiments. At the beginning of September, 1888, I built a 

 temporary wall, diverting the Waikoroihi water away from 

 the Blue Pool. This soon had the effect of raising the tem- 

 perature of the Blue Pool to from 200° to 210° Fahr. The 

 water rose a few feet and began to boil furiously ; then 

 the pipe which I call the Indicator became active, and as 

 soon as this took place the water of the Blue Pool would 

 cease boiling and go down again to the low-water line. I 

 watched this same action for several hours, but unless 

 the water of the Blue Pool rose to the level of the overflow- 

 drain there was no eruption of Pohutu. Seeing that this 

 small Indicator tube acted as a kind of safety-valve, I tried 

 to close it up with bags, stones, &c., but failed, the steam 

 and water finding its way through small fissures in the rock. 

 It then occurred to me to build a kind of dam around the 

 Indicator, so as to collect the water ejected by it, and also 

 lead some of the water from Waikoroihi into this dam, thus 

 causing this cooled water to flow back down the Indicator 

 tube. This had the desired efl'ect. The Indicator stopped play- 

 ing altogether as long as I could keep a small stream of cooled 

 water running down it. On the following day Waikoroihi 

 stopped playing. The water of the Blue Pool rose to the 

 level of the overflow-drain, became more and more active, and 

 on the 9th of September, two days after the works were 

 finished, Pohutu gave a grand eruption, lasting nearly two 

 hours, throwing large volumes of water from 60ft. to SOft. 

 high. This eruption was repeated in the evening, and from 

 that date until December, 1889, it played regularly about 

 twice in twenty-four hours. 



