THE OBLIQUITY OF THE ECLIPTIC, 1 05 



" The Maoris of New Zealand," by Mr. Tregear, published in volume 

 XIX. of the "Anthropological Institute of Great Britain, 1890." The 

 paper has been written in reply to the code of " Questions " published 

 in the "Journal of the Anthropological Institute," volume XVIII. • 

 and next to the essay by the Rev. W. Colenso, on the Maoris, published 

 in the first volume of the " Transactions of the New Zealand Institute," 

 contains the fullest and best account of the Natives of these Islands. 



A. H. 



WHAT CAUSED THE OBLIQUITY OF THE 

 ECLIPTIC. 



The following letter by T. A. Bereman, of Mt. Pleasant, Io., 

 appeared in Science of 13th February. In view of the attention now 

 being given to the subject of Antarctic Exploration, it is interesting 

 and suggestive : — 



" It is difficult to bring the mind to believe that there ever was a 

 time when there were no seasons, — spring, summer, autumn, and winter, 

 — as now. In attempting to account for natural phenomena, we have 

 nearly always assumed that the axis of the earth was originally inclined 

 to the plane of the ecliptic at an angle of 23^°, as we now find it, and 

 of course we in consequence have formed in our minds the idea of the 

 annual recurrence of the seasons through all geological time ; but the 

 elimination of the seasons from the early history of the earth has been 

 forced upon us by the accumulation of facts from the geological record. 

 There is abundant evidence to prove the existence of tropical or sub- 

 tropical animals and plants in Arctic latitudes as late as the tertiary. 

 In Professor Dana's "Manual of Geology" (third edition, p. 352) that 

 author says, ' If we draw any conclusion from the facts, it must be that 

 temperature of the Arctic zone differed little from that of Europe and 

 America. Through the whole hemisphere, and we may siy world, 

 there was a genial atmosphere for one uniform type of vegetables, and 

 there were genial waters for corals and brachiopods.' Scarcely any one 

 now, who is conversant with the facts, will deny that the early histcry 

 of the earth was marked with a uniform, or nearly uniform, temperature, 

 in all latitudes, prior to and including most of the tertiary. The main 

 difference of opinion existing now among scientific men is how to 

 account for such uniform, world climate. 



" So of the glacial period. Everyone admits that the great array 

 of facts justifies the conclusion that the poles of the earth were, since 

 the tertiary, covered with great ice caps or sheets several thousand feet 

 thick, and reaching down to the 40th parallel of latitude, constituting 

 the great glacial period. There is a wide divergence of ojnnion, how- 

 ever, as to the origin or cause of this glacial cold. Mr. Croll, in his 

 'Climate and Time,' has formulated a theory, derived from the secular 

 changes in the eccentricity of the earth's 01 bit, through which he finds 



