Wetlhigton Pldlosophical Societij. 525 



adopted the view that the gradual condensation of water on the earth's surface conse- 

 quent on the loss of its original cosmical heat, had produced the succession of phenomena 

 resulting 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. He adduced as proof of this the existence of 

 fossilized 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 chmate 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 rocks 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 evidence of a minute secular cooling afforded by the succession and distribution of 

 animals and jDlants during former epochs. He considered this evidence very unsatisfac- 

 tory, 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 distri- 

 bution of animals and plants on which the author founded his argument, and con- 

 sequently of the chmate ; 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 supposed sub-tropical fauna inhabited 

 Central Europe, or the temperate flora flourished in the arctic regions. 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 

 gO much as the absence of light in that region for six months of the year, if all other 

 conditions of the earth remained as at present, except a general higher surface tempera- 

 ture. Many speculations had been put forward on this subject ; one of the latest, by 

 John Evans, was that the earth was solid, with an oxydized crust, sei^arated 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 distribution 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 analyses of meteorites, it had only been shown 

 that hydrogen existed. He thought that the order in which metallic elements were 

 found in an oxydized state in the earth's crust was in favour of a theory of gradual 

 cooling. 



