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Origin of Radium

No well authenticated discovery made in the last half century—not even that of the distance to which Hertz waves can be transmitted—has stimulated bolder conjectures than have the announcements of M. and Mme. Curie. What will be the outcome of this speculation cannot now be foretold, but already a number of amazing guesses and theories have been inspired by the properties of ladium, considered apart from the other phenomena of nature. Only a few weeks ago Prof. Rutherford, of Montreal, created a sensation lecturing before a scientific audience in London by suggesting that the earth is much younger than astronomers and physicists have believed. That possibility had occurred to him in consequence of observing the rapid rate at which radium decays. Supposing this to be uniform, he estimates that all which is at present in existence will have' disintegrated in a thousand years, and that all which existed a thousand years ago must now have become transformed into something else—helium, perhaps. Prof. Joly, of Dublin, reaches an astonishingly different conclusion concerning the earth's age, by confining his attention to the behavior of another metal, uranium. It has been observed in a laboratory that this metal apparently breaks down, but much more slowly than radium. Of a given amount of uranium only a ten-thousand-millionth part decays in a year. Adopting that element as a standard, then, the Irish physicist says that 10,000,000,000 years may be regarded “a minor limit to the antiquity of matter in our part of the universe.” Rutherford and Joly cannot both be right, apparently, and perhaps neither of them is. Lord Kelvin's estimate of the time which has elapsed since the globe cooled sufficiently to sustain animal and vegetable life was between 10,000,000 and 20,000,000. Even the most exacting biologists and geologists demand more than 100,000,000. Prof. Joly's guess exceeds these others a hundred or a thousand fold! A good deal of attention is now being given to the probable origin of radium. Whether the element, while still intermingled with other substances in the ores in which it is found, undergoes change as rapidly as it does after separation, is a question not yet answered. However, whether its fixity is greater in the one case than in the other, grave doubts of its permanence are entertained by most of the men who are iiow studying the element. A possibility which has occurred to several minds almost simultaneously is that radium is a product of uraniuri. The two were invariably associated in the pitchblende from which the Curies extracted radium. Dr. Bertram B. Boltwood, of Yale University, has made tests with various ores that lead him to think that the quantities present always bear the same relation to each other. W. C. D. Whetham, of Cambridge, England, says that every time he has obtained what was sold to him as a pure salt of uranium he would find traces of radium in it. He has also examined specimens of uranium compounds that have been preserved in the Cambridge laboratory for periods ranging from seventeen to twenty-five years, and in every instance they contained radium. Finally, Frederick Soddy, who co-operated with Rutherford in some of the latter s earlier work, but is now Identified with University College in London, re ports in Nature a set of experiments which he is now conducting. He obtained a thousand grammes of uranium nitrate twelve months ago. He purified it so that he could detect the presence of only a microscopic trace of radium. The proportion which the amount of the latter bore to the mass of the former would be represented with a “1” preceded by a decimal point and sixteen ciphers. At the end of a year, Mr. Soddy tested again, and found a little more, but not as much as he thought he should have obtained if the added quantity came from uranium. There may have been something wrong with his test, or else with his computations, and Mr. Soddy will continue the observations from time to time. Inasmuch as the amount of radium discovered at the end of the year was only a ten-thousandth part of that which his and Sir William Ramsay's theories promised, he says: “This practically settles the question so far as the production of radium is concerned.... The result, of course, may be explained by assuming the existence of intermediate forms between uranium and radium. But... several such hypothetical forms, each with an extended life, must be assumed. So that, unless modifications are made in the theory which at present are not justifiable, the evidence may be taken as indicating that uranium is not the parent element of radium." Rutherford, in a recent book, published before Mr. Soddy's letter appeared in Nature, said: “Since radium hl!s a short life, compared with that of uranium, the amount of radium produced should reach a maximum after a few thousand years, when the rate of production of fresh radium—which is also a measure of the rate of change of uranium—balances the rate of. change of that product” (into helium). Prof. Joly, after briefly indicating the improbability that radium may be the offspring of thorium, suggests that it may not result directly and solely from decay. Perhaps it may be a combination of the radio-active products of some disintegrating element with one of the many substances found in pitchblende. Particles and properties derived from either uranium or thorium might have united with bismuth or barium, for instance. “Thus radium would represent the synthesis, not the decomposition, of an element,” Prof. Joly adds. He therefore advises that a watch for the genesis of the new element in pitchblende and al- I ied minerals be undertaken. How extensively radium now exists, or has existed, in other celestial bodies than the earth is a question of profound interest both to astronomers and chemists. If positive information on this point could be obtained, it might aid the experts in determining its origin and history in the globe. There has been a disposition to take it for granted that (he slars are all composed of substantially the same materials. By the spectroscope it has been possible to identify with certainty nearly forty terrestrial elements in the sun. Lockyer thought that he saw evidence of several others—uranium among them—in the same luminous envelope of vapor. What is contained at greater depths can only be conjectured, but positive recognition of more than half of the elements found on the earth is certainly suggestive. A still more impressive fact is that a large number of stars—which astronomers say are also suns—give a spectrum like the great body on which the earth is dependent for light and heat. Arcturus and Capella are notable representatives of this “solar” type of stars. Other 1ypes are characterized by different spectra from this one. Instead of showing th') lines of calcium, iron, sodium and nearly twoscore other metals, they betray the presence of little except helium and hydrogen gases. The suspicion is entertained, however, that the dissimilarity indicates differences in temperature only, and not of composition. Although the astronomers are not in perfect harmony concerning the meaning of the lack agreement in stellar spectra, many of them look at the intensely white stars, which give a helium or hydrogen spectrum, as younger and hotter than the yellow, or “solar,” stars; whereas the red, or “carbon,” stars are considered cooler and perhaps older than any of the others. The practical unity of the material of which the whole visible universe is constructed is held to be possible, if not probable; and hence the particular elements which are the most conspicuous in any one group are accepted as indications of the stage of development attained by the members of that family. No one has yet found evidence of the presence of radium in the sun. That fact proves little, though. Radium is one of the heaviest elements known. Astronomical spectroscopists have suggested that the failure to detect platinum, thorium and iridium in the sun and the dubious indications given concerning uranium may be due to their great weight. The same explanation would apply to radium. There is almost as much reason for thinking that the latter exists in the sun and the other stars as there is to imagine that they contain platinum and uranium. The chief doubt is suggested by the belief of Sir William Ramsay that radium is an exceedingly “unstable” element, that the helium which has been obtained from it in a few instances was really a product of transformation, and that the gas was not simply liberated from a previous association with the metal. Of course, if all the radium which ever existed in the universe has now been converted into helium, and if a new stock of ra- rlium is not being manufactured out of other materials, then' the supply has given out entirely. However, neither of these suppositions is yet warrantable. So long as one must rely on guesses alone, he is excusable for thinking that many other bodies besides the earth contain radium, though they do not show it. TUe case for transmutation has not been established, but even if it had been the theory would be applicable to the fresh manufacture as well as the disappearance of this strange element. Whether or not the helium now observed in many of the stars has resulted from the decay of another element or has maintained its individuality as long as its associates, it is found in many of the nebulm and in certain bodies which are involved in “cosmic fog.” In these facts some astronomers find a hint that the Pleiades, the brighter orbs in Orion and certain other conspicuous helium stars are of comparatively recent birth, and that younger sisters are even now being developed out of the same chaotic and tenuous mist. -N. y. Tribune.

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