The Radium Clock.

Oamaru Mail, Volume XXXV, Issue 10016, 5 December 1908, Page 4 (Supplement)

The Radium Clock.

In the crust of the earth exists the most wonderful time-keeper (says Professor Gar-, ret P. Serviss). a clock whose pendulum beats periods of thousands of years, and whose hours are measured by millions of vears. It is the "radium clock" of the geologist Strntt, a natural machine, which has been called ceaseless and perpetual but which Professor John Joly avers will eventually run down and come to rest, like everything else. The beating of this strange clock drives the life blood through the arteries_ of• the globe—such is the hit-' est word of science. It is a temperature chronometer. Its action depends upon the alternate accumulation and dissipation of heat, and as it runs on it changes the face and complexion of the earth.* It is the active agent in the production of the successive revolutions which transform

our planet, replacing continents with seas ■ and seas with continents; valleys with mountains and mountains with plains and valleys. From the operation of this great clock of the ages, Professor Joly has recently told the .British Association of the Advancement of Science, "'possibly have come and »one those continents which ' many believe to have once replaced the waters of the oceans, and which, with all their wealth of Jiie and scenic beauty, have disappeared so completely that they scarce have left a wreck behind. But those forgotten worlds,'' he continues, "may be again restored, lhe rolled-tip crust of the earth is still rich in energy borrowed from earlier times, and tuc oloiv but mighty influences of denudation ..and deposition are forever at work. And so, perchance, in some remote age the vanished Uondwana Land, flie lost Atlantis, may ouce again arise, the seeds of resurrection even now being sown upon tneir graves from >he endless harvests of pelagic life.' : How 'does this marvellous clock, buried in the .earth, oring about these evolutions? What is its method of action? In reply it must be stated that radium for some reason not yet definitely determined, is more abundant in the surface strata of the earth than in its interior. -- is found in all the rocks accessible to us, and in the ooze of the ocean's bottom, but the temperature of the earth as a whole shows that it cannot be equally abundant deep down in the globe. This fact indicates the mime motor of the "radium clock," as far as it affects theological revolutions. Consider, for instance, the broad floor of the sea, upon which continual deposits are being made in eonseouence of the wearing down of the continents. The accumulation of pelauic deposits gradua.." depresses the strata containing radium, until at last they are buried tens of thousands of feet deep. With this burial come 'an increase of temperature, varying as the square of the depth. Radium is continually giving off heat wherever it may be, but when the stratum containing it is pressed down beneath a load of sediments miles in depth, the accumulation of heat becomes very gre-;. Then the rocky mass expands and tends to rise ; the bottom of the ocean emerges and turns to land; the sea :nves place to a continent, while other continents sink and become the beds of new seas. Th's process has recurred more than once in the histoTy of the earth, but now for the first time the agency of radium in caryinff it on has been pointed out. Mountain ranges, as has long been known, exhibit, throusrh a vertical range of many thousands of feet, successive beds of rocks which must have been laid down at the sea bottom. The sediments that eventually rose, from the sea bottom and formed the Appalachian Mountains were, according to the jreolocist Dana, 40,000 feet in depth, a vast pile of horizontal beds laid down through the course of ages by the. water. The pile of sediments that rose into the Wahsatch Mountains was 60,000 feet in depth. It has always been more or less a mystery to geologists—this fact that wherever an immensely thick deposit of sedimentary material is formed an elevation subsequently takes place. They have found tentative explanation, but none so satisfactory as that now elaborated in the hypothesis of the "radium clock." It is not clpnipd that the compressive stress in the crust of the globe, settling upon its shrinkinn- interior, may be the primary factor in geological movement, hut the rise of the ocean bottoms after the sediments have attained a certain depth is better explained by the new theory. "We have, in these effects," impressively says Professor Joly. "an intervention of radium .in the dvnamics of the earth's crust which must have influenced the entire history of our <rlobe. and which I believe affords a key to the'instabilitv of the crust. For after the events of mountain building are accomplished stability is not attained, but in the presence of the forces of denudation the whole sequence of events has to commence over again. • Every fresh accession of snow to the earth, every passing cloud contributing its small addition to the torrent, assists to spread out once more on the floor of the ocean the heatproducing substance (radium): With this rhythmic succession of events appear bound up these positive and negative movements of the strand which cover and uncover the continents, and have swayed the entire course of evolution of terrestrial life.