584 Transactions. — Miscellaneous. 



During the time I was absent from the colony as Com- 

 missioner at the Paris Exhibition there was no one on the spot 

 to look after these special works. The consequence was that 

 Pohutu again stopped playing regularly. On my return, in 

 February, 1890, I was informed that Pohutu had not played 

 or been in active eruption for the last nine weeks. I at once 

 went over to see it, and, finding that the works I had ma.de had 

 been tampered with, I had them put into temporary repair,^ 

 with the result that Pohutu played up again a few hours after 

 the work was finished; and its action has continued ever since, 

 though not so regularly as before, but this is no doubt only due 

 to the defective repairs of former walls, &c. 



As a further illustration of what may be done in regulating 

 the action of geysers, or even in creating or starting new ones, 

 I may state that in the Sanatorium grounds there are two hot 

 springs, with concrete basins around them, which were never 

 known to have geyser-action, though the formation of the sur- 

 rounding rocks shows that they had been geysers at some remote 

 period. These springs supply the hot swimming-bath, but during 

 the year 1889 they had gone so low, and were so much in- 

 fluenced by the atmospheric pressure, that sometimes they 

 would remain for several days 2in. or Sin. below the level of 

 the outflow-pipe, thus discharging no water. This became a 

 matter of great importance, as the bath, which had cost £1,000, 

 threatened to become useless, owing to the impossibility of 

 keeping it at a proper and regular temperature. 



It occurred to me that by contracting the springs proper 

 into pipes it would prevent the hot water from becoming cold 

 by admixture with the water in the basin, for I had noticed 

 that when the springs were active the temperature of the water 

 of the basins would rise from 140° minimum to 180° maximum. 

 I thought that this increased activity of the springs when the 

 water was hot was owing to the difference in the specific 

 gravity between hot and cold water which the spring-tube or 

 fissure might contain in its column, and that this difference 

 might be sufficient to cause the water to rise a foot or two 

 above present level, according to the depth at which this in- 

 fluence (on the temperature of the water) would take place. I 

 had some temporary works carried out to prove the correct- 

 ness of this theory, and to my delight found that it was quite 

 true, and that, instead of a small rise of 2ft., which would have 

 been quite sufficient for our purpose, there was force enough 

 in the springs under these altered circumstances to form 

 geysers. Having further acquired the knowledge that the 

 whole of the springs contained in the Oruawhata and Chame- 

 leon basins were hydrostatically connected, I arranged a 

 system of pipes over the three principal springs, connecting 

 each of them by secondary pipes to three valves, by means of 



