WELLINGTON PHILOSOPHICAL SOCIETY.

New Zealand Times, Volume XXXII, Issue 5119, 20 August 1877, Page 3

WELLINGTON PHILOSOPHICAL SOCIETY.

There was a fair attendance at the meeting of this society held on Saturday evening. After the confirmation of the previous meeting’s minutes, and the announcement of Mr. B. T. Chaytor and Mr. Robert Govett as newly elected members, the President (Mr. W. T. L. Travers, F.L.S., M.H.R.), read his paper on “ Remarks as to the cause of the warmer climate which existed in high northern latitudes during former geological periods. This paper was a review of the progress recently made in our knowledge of the subject, and especially the bearing of Naysmith and Carpenter’s examination of the moon’s surface, and the work by Mathew Williams on the “ Fuel of the Sun.” The author adopted the view that the gradual condensation of water on the earth’s surface consequent on the loss of its original cosmioal heat, had

prOClUCea lII© BUUufbsiuu ui icamuing in the present distribution of life. That in consequence of the cooling having taken place first in the polar regions, it was there that the higher and latest-formed organisms must have first appeared. Ho adduced as proof of this the existence of fossilised vegetation within the Arctic regions which had almost a tropical character, and other evidence that during successive geological epochs the changing character of the fauna and flora in other regions showed that the climate had gradually become more and more temperate. Dr. Hector would only speak as regards the geological aspect of the author’s paper. The fact that the oldest rooks we know are either hydrated or formed by the action of water as sediments proved that our 'geological records did not carry us back to a time when very high temperature prevailed. It was only, therefore, necessary to enquire into the evi-

the succession and distribution of animals and plants during former epochs. He considered this evidence very unsatisfactory, and not leading in the direction the author required. The former existence of temperate plants in high latitudes took place at a very late period in the earth’s history, and long after some temperate regions had possessed a fauna and flora similar to that at the present time- There had in fact been several repetitions of the abnormal distribution of animals and plants on which the author founded his argument, and consequently of the climate ; so that these changes could hardly be referred to the progressive cooling of the globe as a whole. The inferences made had chiefly been drawn from late tertiary strata ; but in the case of New Zealand there was evidence that the same type of vegetation had survived since the early part of the cretaceous era, a period twenty times as great as that which had elapsed since the supposedsub-tropical fauna inhabited central Europe, or the temperate flora flourished in the Arcticregions. From this it was surely to be argued that the cause had not been one of universal operation. Concerning the former Arctic flora the real difficulty was not the question of temperature so much as the absence of light in that

region for six mouths of the year, if all other conditions of the earth remained as at present, except a general higher surface temperature. Many speculations had been put forward on this subject ; one of the latest, by John Evans, was that the earth was solid, with an oxydised crust, separated from the central nucleus by a viscous layer of unequal thickness, in which chemical combination, or, as it may be called, the “ rusting process,” was still active. The elevation of mountain masses by the fracture of the crust would act like weights on a gyroscope and lead to a gradual displacement of the outer crust with reference to the axis of rotation of the interior bulk of the earth, which astronomers required us to believe to be immovable. He also pointed to recent researches of Professor Duncan regarding reef-building corals, which at the present time are confined to a narrow equatorial belt, but in eocene times that belt appears to have had a distribution oblique to the present equator. If this were established it would offer a still greater difficulty in the way of accepting the view that the changes in distrbution of climate were due to the secular cooling of the earth as a prime cause. Dr. Newman did not think there was any evidence of water in interstellar space. From spectroscopic observations and the analysis of meteorites, it had only been shewn that hydrogen existed. He thought that the order in which metallic elements were found in an oxydised state in the earth’s crust was against a theory of gradual cooling. Mr. Kikk agreed with Dr. Hector regarding ) the difficulty in understanding how such plants as magnolia and the tulip tree could not only exist but perfect their flowers and fruit where light was absent for six months of the year. The absence also of all forms of low plant life, which might naturally be expected under such circumstances, required explanation. Mr. Cox thought the author had overlooked the evidence of former glacial periods at successive intervals as far back as the Devonian epoch, with intervening periods, during which warmer conditions prevailed.

Mr. Martin Chapman said that unless the oldest formations were proved to be sedimentary, the presence of water in them would prove nothing, as water must infiltrate the deepest rock we can reach. He thought the tempei ature at which plant life could exist had been understated, from his having collected organisms in the hot springs in Hecla (Iceland), which had a very high temperature. Mr. Carbdthers thought that the paper was so important that its discussion should have been deferred. He thought it not yet proved that there was a central heat, and certainly not that it could influence climate. The argument derived from increase of temperature with depth in the earth’s crust only proved a modified form of volcanic action—in some places greater than in others. The greatest depths to which we reached were the bottoms of the oceans, and there we found no evidence of a higher temperature, but the reverse. In open oceans it might be argued that this was due to the removal of the heat by currents ; but in the case of the Mediterranean, and also in Loch Ness, which are deep holes without an outlet, excepting for the surface water, the temperature at the bottom is the same as the average winter temperature of the air at the surface. In the Nebular theory heat had always been assumed as being the expanding force which was gradually lost, but this was not proved. Cosmical dust is not kept apart by heat, but by the continuous motion of the particles. He thought the balance of evidence was against the theory of central heat. If the earth had once been hotter it would have become smaller in cooling, and its velocity of rotation would have increased; but this’ was contrary to fact, as the rotation had been retarded by about three hours since exact observations were first made. With regard to what had been said about the thickness of the earth's crust, the existence of tides proved that it must be so great as to be absolutely rigid. He considered it quite possible for plants to live in darkness if they remained dormant, like geraniums, which are placed in a dark cellar during the winter. Mr. Travers, in reply, said he had not advanced any theory of his own, but merely wished to direct attention to views that were gaining ground. He thought that when geologists had studied the works to which h<* had referred, they would very much alter their present opinions on the subject. Owing to the late hour at which the discussion terminated, several papers were held over for next meeting.