PECULIARITIES OF RADIUM.

Otago Witness, Issue 2565, 13 May 1903, Page 65

PECULIARITIES OF RADIUM.

JHE NEWLY-DISCOVERED METAL THAT GIVES PERPETUAL HEAT. Scientists all over the world are deeply aroused by experiments being made with radium, the remarkable new metal which possesses ths power, hitherto accredited only to the sun, of constantly' emitting light. Its strange properties entitle it to be ranked as one of the freaks of nature, and give it a glamour of fascination which not even gold or diamonds or precious stones can put to the blush. But radium resembles these metals no more than it does a turnip, except in its extreme rarity and preciousness. A diamond would be a cheap bauble in comparison with this costly metal. Sir William Crookes is quoted as saying a pound of radium would cost 1,000,000dc-l, and there is not so much as 21b of it altogether in existence. In its purest form it is practically priceless. A king's ransom would hardly suffice to buy a quantity the size of a gunshot. The mysterious light-giving nature of the new metal is still further enhanced by the fact that no source of its energy is -apparent. Like the sun, it is self-sufficient, and goes on giving light for years without seeming to replenish its power or to be diminished by the energy it expends. No other metal or substance has such a powtr. Its peculiar properties have given rise to much discussion and to the promulgating of new theories. In some degree investigations have already cast a- doubt upon the veracity of the accepted theories of light and matter. Whether the wave theory of light must be abandoned for the old corpuscular idea of its composition and the atomic theory of matter renounced as untenable remains to be seen. The new discovery has already thrown fresh light upon the nature of both light and matter, and further developments may be looked for. In the laboratories of the world every d a y — and at night, too, when the weary masses sleep — patient scientists are ever pondering, experimenting, and calculating. Humanity at large knows little of these vigils until, in the fulness of time, the fruits of some world-astounding discovery appear in a sudden blaze of glory. Then come venerable theory by which generations have lived and died becomes a back number, the frontier of the known is pushed out a little further into the mysterious hidden realm, and humanity has advanced another step in the stride of power. Since the time when nvsn quit searching for the philosopher's stone and the get-rich-quick method of transmuting the baser metals into gold, in a process of gradual acquisition the composition of the material universe steadily has become a subject of common kuowledge, until he who runs may read. Now one metal, now another has been added to the list, and it" has seemed until within recent years ihat our analysis and classification of the elements was a thing well nigh complete. No less thin 70 separate elements were known, of which 57 were looked upon as metals, the remainder being non-metallic. Continued investigations, however, have brought out the fact that locked up in the secret breast of nature are still other metals, or elements, and these are being drawn forth to the wondering scrutiny of the scientist. Most of thes2 discoveries have been made well within the past decade. Of the new metals some are of great interest from the scientific point of view, but, because of their extreme rarity, do not promise to be of economic importance. On the other hand, it is impossible to foresee what wide and far-reaching effect some of. them may have in opening up new lines of thought and leading to still further discoveries. In this direction the possibilities 'of radium are immense. To-day this metal is attracting more attention 'rom scientific men than did the now famous Rontgen rays, and the foremost scientists of England, France, Germany, and America are conducting experiments to determine further its precise nature and its relation to the rest of the material universe. In Europe, besides the original discoverers of the substance, such men as Sir William Crookss, Professor J. J. Thompson, of Cambridge, and Lord Kelvin, to say nothing of a host of others, are treating it in their laboratories. The enthusiasm is reflected by scientists in America. Professor Charles F. Chandler, head of the department of chemistry at- Columbia. University, says the whole matter is still more or less in the dark, but they are giving special attention to it in the laboratory nnd awaiting developments One of the few specimens of the metal in America is the property of Columbia. A glass tube containing a small quantity of this new element, in the form of chloride of radium, was put on the table. It looked like nothing more or les? than a white powder. Probably no man in America knows more about radiuni than William J. Hammer, consulting electrical engineer of New York, who is in clo.se touch with the leading investigators abroad, and lately presented a paper on radium before the American Institute of Electrical Engine:rs. Mi Hammer has in his possession six or seven small tubes of the pieeious metal, which he obtained through the courtesy of the discoverer. Professor Curie, of Paris, and exhibited for the first time publicly in America. All the specimens of radium so far in existence are chlorides or bromides of radium. . In other words. L he metal is found in combination, and has not yet been obtained in its pure metallic state. The first discovery was made about six years a^o, and came about iD this way : When Rontpen announced ]n 1895 his discovery of thi X-rays other investigators were quick to take up the study of radiation and radio-active matter. As is well known, a striking feature of the X-ray is its abiliry to make various substances fluorosce — tint is. to become self-luminous trhila ggsosed to the action of the rays.

This was the starting point for the study of radiant energy and radiant matter. One of the most distinguished experimenters in this field was Sir William Crookes. He found that by passing a powerful charge of electricity through a vacuum tube exhausted to one-millionth of en atmosphere molecules of the gas in the tube were thrown out from the negative pole in streams strong enough to set a finelybalanced wheel in motion These very minute projected particles were called by Crookes radiant matter oi electrons. They are infinitely smaller than atoms which in the natural state have been regarded as the ultimate division of matter. A few year 3 ago M. Henri Becquerel made the remarkable discovery that the metal uranium possesses the property of giving out radiations identical in nature with the electrons or radiant matter of the Crookes tube. Experimenting along the same lines, Mme. and M. Pierre Curie, of France, found Bohemian pitchblende and two other compounds of uranium possessed the powers of radiation in a remarkable degree, from which they inferred the presence of some other substance stronger in radiating power than uranium. After much labour they were rewarded by finding a new metal, similar to pure bismuth in chemical qualities, but far more radiant. This they named "polonium.' On continuing the search they found another metal, chemically lika pure baviam, but possessing a marvellous degres of radiating power. They nam-ed it "radium." Here were two new metals discovered, and a little later Debierne found a third, not unlike theorium, which he called "actinium." None of the thres new elements lias as yet been obtained in an absolutely pure state. Radium is far and away the most interesting of them all, both to the scientist and the layman. It has a special spectrum of its own and an atomic weight of 225. It is at the present time being made the subject of spacial experiments in the laboratory of Professor Curie, at the Ecole de Physique et de Chiinie. Industrielles. Few scientists in America have had an opportunity of examining this strange substance, inasmuch as it is extremely rare. In the last four years not much more than 600 grams, of all grades of purity, have been manufactured. That made in Gcrmanv is not well refined. The best product is made in France, some of which will shortly be on tin American market at a cost of from 6000dol to 10,000dol a gram, the gram being 15.432gr in English weight. All of the radium manufactured in France is made under the direction of Professor Curie. The best quality has 7000 times the activity of uranium, which is 20 times the power of the best German product. In order to get a kilo, or two and onefifth pounds, of radium as much as 5000 tona of uranium residues would have to be treated. All the salts of radium are more or less radio-active, but the most luminous ompounds ara the chloride and bromide. Not a few substances, like sulphate of lime, and compounds of uranium, calcium, and barium, if exposed for some time to a strong light or subjected to heat vibrations, have the power of glowing brightly in the dark. Radium, on the other hand, stands by itself in the property of giving light of its own accord and without being treated in any way. In the same manner it will go on emitting the glow for months and years. It has the further property of producing a similar light-giving power in other substances that come within its influence — a power which they continue to hold for a long time. The radium rays appear to be of two kinds, both of which are emitted at the same time. One kind bears every resemblance to the X-rays, whereas the other Is identical with the rays given out from Uie negative pole in the Crookes tube. The electrons, or minute particles that cor-n-pose the radiations, are now looked upon as the very substance of electricity itself, and many scientists think that through the study of them an approach is being made to the solution >f that bailing question, What is electricity? At inyrate, radiant matter or electrons are creating widespread discussion , and form the basis for an electron theory of electricity. Radium gives off its rays with a varying velocity that is sometimes as great as 100,000 miles a second, or about two-thirds the velocity of light. Speaking of this tremendous velocity. Sir Willi-un Crookes has said the energy of one gram of electrons given off by radium is enough to lift the whole British navy to the top of Ben Nevis. To account for the energy of the radium rays is a puzzle. It i? conjectured by some persons that the energy is liberated by the breaking up of atoms into electrons. but, wlntevoir is the ;ause, radium has a radiating power 900 times as great as that of uruni'im, the next most powerful metal in the same class. It might seem from these figures that a metal diffusing itself abroad with such energy would toon vanish in an invisible dust of electrons, but in reality the discharges are so minute that the loss of matter would not exceed one milligram (or onethouMindth part of 15gr) in a, thousand years. Recently, however, Heydweiller, a German physicist, has made some experiments in which he shows there is a :onsiderable loss of weight. Like the Rontgen rays, the radiations of radium have the power of carrying negative charges, of discharging electrified bodies some distance, of rendering the air a conductor, and of imparting these fame powers to many other bodies. If some radium salt be brought near a charged electroscope the gold leaves will at once fall together. The rays will cause an X-T*ay screen to fluoresce. and any diamond or gem will shins in the dark if brought near radium salts. Ihe rays have a power of penetrating opuaquo substances. On all scores the new mrtal is powerfa. The smallest bit placed upon the skin wiii raise a blister that takes months to heal. A pound of it put in a jar on a table would blind and burn those in the room so that death must ensue. These are no ] fancies.

In the course of his experiments. Professor Becqusrel put a tube containing a small amount of the chloride of radium m his vest pocket and left it there for six hours. In a few days a sore developed on his body on the spot directly opposite the vial. It took seven we2ks to heal. A glass tube with a small quantity of the metal was tied to the coat sleeve of another chemist. In two hours a burn resulted through the clothing which was not completely heated for several months. These physiological effects, which everyone will recognise as identical with burns from the Rontgen ray. have been demonstrated as well by M. and Mme. Curie, who. in the course of handling tubes, received numerous burns on the hands and finger tips, which fim appeared as a redness, developed slowly, and ended in a sloughing off of the injured skin. — New York Press.