Page:Transactions NZ Institute Volume 9 Supplement.djvu/15

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Wellington Philosophical Society.
623

to their condition at the time of the Maori invasion, would be found in a pamphlet, now very scarce, published by Dr. Dieffenbach, the naturalist to the New Zealand Company, about the year 1840.


2. "Notes on the Influence of Atmospheric Changes in the Hot Springs and Geysers in the Rotorua District," by Capt. Gilbert Mair. (Transactions, p. 27.)

Dr. Hector pointed out that the district in which the Hot Lakes are situated, is a wide valley, extending from Tongariro to the Bay of Plenty, barred at intervals by volcanic rocks, the débris of which form intervening plains. The supply of water for the Hot Springs was, no doubt, derived from the rainfall in the upper district, only a portion of it being carried off by the Waikato River. The remainder in filtering through the strata must come in contact with lavas, which are still hot or perhaps undergoing chemical rearrangement, and this gives rise to the high temperature of the water when it reaches the surface. Geysers, like other volcanic phenomena, are well-known to be dependent on changes in atmospheric pressure, but the statement of the author that their activity had a daily periodicity—only affected by the direction of the wind—would appear to require some other explanation; and, as the author stated that his results were only quoted from memory, he thought that a more accurate study of the phenomena would probably show that they were not exceptional. The geysers and hot lakes in White Island are certainly affected by the state of the barometer.

Mr. L. H. B. Wilson confirmed Dr. Hector's remarks about the variability of the lake at White Island, and stated that at the time of his visit it was almost dry.

Mr. Carruthers thought that more accurate observation was necessary. The supposed regularity in the eruptions of the geysers might be due to the coincidences only being observed, just as sailors come to believe in the influence of the moon over the weather—a theory which has been proved to be incorrect.

Mr. C. O'Neill considered that observations should be made to determine how far the accumulation by waves, due to wind affecting the level of the lakes, influenced the level of the hot springs.

Mr. W. T. L. Travers thought that the fact of the springs having different times of intermission—even in close proximity to one another—proved that the intermission could not be due simply to barometric pressure.

Captain Mair, in reply, said that the changes he had observed were beyond all doubt. The Maoris, who were very close observers of nature, had noticed the fact for generations. He thought that atmospheric pressure on a large water surface at a higher altitude might afford an explanation.

Mr. W. D. Campbell remarked, with reference to the last statement that had been made, that, as atmospheric pressure acted vertically, its influence would be exerted irrespective of the size of the orifice through which the water was ejected.


3. Dr. Hector exhibited photographs of a reported Moa head, found near Tauranga, which proved to be the head of a Goosebeak Whale (Epiodon chathamensis), or a closely-allied species.


4. He also drew attention to a fine collection of stone implements from the Copenhagen Museum, which had been presented to the Colonial Museum by Captain Rowan, of Taranaki.


5. The President exhibited a species of Gordius, or Hair-worm, obtained by Capt. Mair in the Lake District.