204 JOURNAL OF SCIENCE. 



The geysers immediately attracted my attention. Waikite geyser, 

 at Whakarewarewa, which had been quiescent for about ten years, again 

 burst into full activity, with eruptions about every quarter of an hour. 

 Pohutu, Wah'oa, and the other geysers were also playing occasionally, 

 but were very irregular in their action. Sometimes weeks would elapse 

 without one or the other of them showing any signs of activity, whilst 

 at other times they would be active for several days in succession. 



Not having had a long acquaintance with the district, I made 

 inquiries of old residents (European and Maori) for any theory to 

 account for the inequality in the thermal action of these springs and 

 geysers. The generally received opinion was that these geysers Avere 

 influenced by the wind — with southerly winds they were quiescent, and 

 with northerly they were active. As I could not well understand how 

 the wind could affect geysers or springs situated in sheltered positions, 

 I began a system of personal observation, and soon found that southerly 

 wind meant high barometer and northerly a low one; and if I could 

 not understand the wind theory, I could understand the hydrostatic 

 effect and the influence of atmospheric pressure, which was simply 

 equivalent to a reduction in the column of water. Every spring and 

 geyser being naturally hydrostatically balanced, the reduction by any 

 means of the weight of the column of water should bring a corres- 

 ponding increase in the activity of the spring. Acting upon this theory, 

 I determined to experiment privately ujDon Te Puia, a thermal spring in 

 a secluded spot near an old pa, on the right hand side, and well down in 

 the bed of the Puareuga River, therefore less influenced by winds. It 

 was at that time boiling, but not very actively. By means of a drain 

 which I cut in the sand formation by the level of the river, I removed 

 about two feet of the water of the pool which formed around the spring. 

 This removal of two feet of dead water had an immediate effect on the 

 spring ; it began to boil furiously, and a few minutes afterwards burst 

 into a geyser, throwing water from 30 to 40 feet high, discharging at 

 the same time the whole of the dead water of the pool. I watched this 

 eruption of what I thought a new geyser, for there was vegetable 

 growth of several years' standing around it, with wonder and with a 

 certain amount of anxiety, as I began to fear that I had started some- 

 thing which I could not control. However, after a few minutes, taking 

 advantage of a decrease in the eruptive force, I ran to the drain I had 

 made, and refilled it as quickly as possible, causing part of the water 

 thrown up by the geyser to be again caught in the pool or basin. It 

 soon accumulated, and after a while the geyser action ceased, and the 

 water of the pool ran down the geyser's tube, together with a consi- 

 derable quantity of water from the river, which had flowed back 

 through the partially closed drain. In about ten minutes the tube was 

 filled with cold water to the surface. 



I watched it for a while, and saw the water getting hotter and 

 hotter. Eventually it began to boil, but without any geyser action. 

 After a time I again opened the drain, and almost immediately there 

 was another splendid eruption similar to the former. I determined to 

 to allow this to play and see what it would do, as I began to have some 

 confidence in my ability to control it by the same process as before, if it 

 was found necessary. It played for about twenty minutes, the geyser 



