Changes of Climate.

New Zealand Mail, Issue 999, 24 April 1891, Page 4

Changes of Climate.

Every now and then articles appear in various periodicals endeavouring to explain the wonderful changes of climate which the undeniable evidences discovered on the earth’s crust prove to have occurred on this world. An instance of this is the article which came out some little time ago in Good Words, on ‘The Heat of the Sun,’in which it is stated that opinion is divided as to the origin of these great climatic changes, but that they are not caused by any difference in the heat of the sun. A wonderful discovery has of late been made in astronomy, which gives a satisfactory and comprehensible explanation of the great changes of climate on the earth. Besides the diurnal rotation of the earth on its own axis, and its yearly motion round the sun, there are two other motions extending over such (to us) long periods as to have no perceptible effect, but having a real and important; effect only noticeable by us in geological evidences. One of these movements is that caused by the progress of the sun itself, which, as it sweeps onward in its own motion towards or round some unknown point, bears along with all its attendant planets, so that our earth in its motion round the sun actually never travels again precisely in the same orbit, but is every year speeding through a different portion of space to what it traversed the year before. The fourth motion of the earth is that by which it gradually alters its position with regard to the sun, turning completelj’ over in the course of 37,000 years, so that in that time where the North Pole now is the South Pole will be, and during these periods every portion of the earth comes in turn within the arctic circle, and in turn within the tropical zone. This perfectly explains how glacial evidences are discovered in those parts now subject to torrid heat, and tropical fauna and flora are discovered within the present arctic regions. Darwin observes, in his ‘ Origin of Species,’ that the effects of the glacial period did not extend over the whole earth at once, and there is evidence to show that when the now arctic regions were tropical there were temperate zones adjoining and arctic zones also in relative positions. This movement, therefore, satisfactorily explains much that has hitherto puzzled some of our gi-patest thinkers. The extremely gradual change would have no fatal effect on the liring creatures of the earth, which would merely have to move their habitat gradually so as to live always in the climates best suited to them. This fourth motion i 3

exemplified by the other plaueta which are all in various stages of it. Mercury is very nearly upright, being inclined only 70 to the plane of the ecliptic. "Venus, on the contrary, is nearly half over, being inclined no less thau 75* towards the piano of her orbit. The earth is inclined 23 s 2S', Mars is a little further over than the earth, as he leans 28* 25' towards the plane of his orbit; but Jupiter, the next large planet, is nearly bolt upright, being inclined only 1° 18' 53". Strange to say, the declination of Saturn is not mentioned in two English elementary astronomies to which reference ha 9 been made, but in the German encyclopaedia, ‘Die gesamniten Naturwissensohaften,' by Hermann Masius, 1887, it is given as 2* 29' 37", so that it is nearly perpendicular. Uranus on the other hand is so far over that his axis is nearly level with the plane of liis orbit, so that in one part of his path his northern pole is turned directly towards us, and at the opposite part the southern pole is as directly turned towards the earth,jand as, whatever the position of a planet, its satellites continue to travel for the most part near the level of its equator, the bowed down position of Uranus causes his satellites to appear to us as if they travelled backwards. As the spinuing round of a planet on its own axis causes it to flatten at the poles, and to bulge at the equator, the fourth motion now under consideration may also assist in maintaining the globular form of the earth. From this brief review of the positions of the planets with regard to the sun, it will be seen that there is nothing incredible in this recent announcement of science that in process of time the earth turns itself right over, and causes gradual but distinct changes of climate to operate on every part of its surface. Nature seems to carry out a system of succesive use of different parts of the earth. At one time the Amazon region in South America was thickly inhabited and was the arena of remarkable civilisations. Now it is densely covered with forest. Eormerly Europe was densely covered with forest. Now it is the arena of remarkable civilisations, and is becoming thickly populated. It is often attempted to prophecy what will hap Den in the future by what is happening in the present. Such, is the prophecy lately made and much noticed, that the Chinese will be the coming race. As well might we prophecy when we see a tree making rapid growth every year that at length it will reach the moon. Ear oat in the ocean there is Easter Island, bearing in its small area the relics—the wonderful relics of some ancient civilisation. The immense statues are built of mighty stones, concerning which much might be asked, as to where they were quarried, how conveyed and how placed in position, and other unanswerable questions. In a building are stone slabs inscribed with an unknown language. Perhaps if we could read them we might find thereon a prophecy that the race from which these inscriptions emanated was destined to conquer and people the earth, But where are they now ? ' Even the very continent upon which they must have flourished is gone—gone to lie fallow for ages and ages, until, recuperated and refertilised, it slowlv emerges again for the use of man. when perhaps Asia may be taking a rest. The great hope for the spread and continuance of the English-speaking race is the indomitable way in which they determine to accustom themselves to every kind of climate, and in doing so prepare their race for almost any change of climate on the earth. Excelsior.