A COLDER PERIOD.

Taranaki Daily News, Volume LII, Issue 172, 13 August 1909, Page 2

A COLDER PERIOD.

hi tin' latest number of Public Opinion to baud appears a highly interesting contribution by Major 11.' A. .Marriott on the subject' of Drayson's theory of thi' cause of the glacial epoch, apropos of Lieutenant Nhackleton's report of til.' Polar Ice Cap. Major Marriott purlieuiiarly draws attention to the observations of the Antarctic expedition regarding the retreat of Polar ice. reviving the theory of Drayson regarding Hie second rotation of the earth. According to Dravson in his "Thirty Thousand Years of the Earth's Past History," the earth has a second rotation, whereby the northern semi-axi„ of the earth describes a conical movement round a point in the heavens removed some six degrees from the Pole Star. This movement is, of course, partaken by the southern semi-axis, The effect of this movement is to cause the earth's axis to vary in

its inclination to the ecliptic. If this' movement of the semi-axis-of tile earth does lake place, the result is a gradual change from a period of extreme conditions yearly of a tropical summer and an arctic winter in the temperate latitudes of both hemispheres to years of move genial conditions of cooler summi rs and warmer winters. At the cnldea't time of this evele, which cover 111 ,OS2 years, the Arctic circle, as has been stated, would extend in the north to the latitude of England and in the south

to the latitude of the south of New Zcalaa.l. According to this theory, it was the year 13,541 B.C. when the extreme of the glacial period was attained,

and the year 5(H4 li,C. when the more mild conditions began to supervene.

which brings us nearer to historical times. By the same reasoning, only

some four hundred years remain ahead of us until the milch ! '■■ r'od of the cycle is reached; nt.cr. i..'.. we shall again enter into the evele of increasing cold. Finally, ill MOD A.D. the nonhabitable lands of the middle latitudes will be again invaded by another sheet of ice, probably fnore extensive than the former one.

"At Ihe past date of o(124 8.C., when the climate of the temperate zone en lered more modern conditions, look place the great migration of Neolithic man, Spreading from the subtropical regions to Central Europe. The abrupt transition everywhere manifest where there are remains of man, from Palaeolithic to Neolithic implements, bears witness to a s'uilden inlliix of more civilised races into regions which had been hitherto as impenetrable to them as fireenland is to us to-day. From many oilier points of view geological evidence is entirely in favor of thi*'theory. The intermingling of arctic and tropical fossil remains is just what might have i/ccn ex|>eclcd under these conditions, but would be a perplexing feature on any other hypothesis. The mystery of the migration and nesting of certain birds over such a wide extent thus receives a partial explanation, and the Indications of ice and iceberg action in various places' which appear go recent are thus given a date more in accordance with the evidence of the rocks themselves than.is the very remote date, some 80,000 years ago. which is assigned by astronomers to the I'st glacial epoch.

■ "The time of the extreme of mildness when Ihe summer and winter climates will approach each-other in character is | only di.iant foil,- hundred years hence. A little consideration will show that we may exnM a somewhat sudden change in the conditions of summer and winter, and that this change ha.s- perhaps at* ready begun. Masses of ioe have the nniperti- of not beginning to melt until the whole mas's is warmed up to 32dcg. I'.. B o that there will be a critical period when the arctic spring begins to overcome this resistance of the ice to physical chaise (the so-called latent heat), and the change will then occur with great rapidity.

"'Cam- the imagination past the four liunilrcil years to come into the lean years of increasing glaciation (writes Major Marriott I. What then? Thesis.', nificance of flic ice age is this, that, whatever the cause, it is'bound to recur. When the ice ago has these latitudes again in its grip, how will it have been met? Where will the activities of the races of the temperate zones have been '■• Mitred? Who is to reap and gather in th" narrowed .world of the tropics? The white man or the yellow? fmaiiinution J rails to grasp the chained asnect of the world. Can It be that in this wonderfully balanced world of ocean, continent., and at'nosnherc. of conditions certainly j !inii|iic in (he solar System, it is part of the scheme to thus nut a term to (lie I destiny of man? Or-will It only serve to marl; the bcrraiiinsr of another chapter I in the evolution of the human race? I '"The 'second rotation,' as explained by Dravson, is vastly different fjom flic 'peglop' rotation of astronomers which is poimlarlv given, but which a little fhiiuahl. will show to be opposed to the ordinary laws of motion. In the first place, any externa}, force acting on the '

earth could only cause a movement which would affect the north mid south poleg to an equal degree; and, secondly, if the south pole can be assumed to be fixed while tho whole axis describes a cone, then it. must be assumed tlult the earth's centra of gravity departs from the line of the earth's orbit. "The dictum of astronomy that 'the pole of the'ecliptic described a circle round the pole of the heavens' as a centre, but constantly varied its distance from that centre,' appeared to Drayson so far from satisfactory that he set himself to Had what actually was the central point, and thus was led to discover, after many years of computation anil research, the second rotation of the earth, requiring 31,GR2 years for its Mjmplotion."