THE WONDERS OF RADIUM.

King Country Chronicle, Volume VI, Issue 466, 18 May 1912, Page 6

THE WONDERS OF RADIUM.

An interesting and informative popular lecture upon the wonders o" radium was recently delivered before the members of the Authors' Club in London by Sir William Ramsay, K.C.B. In- describing the wonders of this clement, the eminent chemist confined himself mainly to a description of his own investigations and experiments. In dealing with the Alpha particles, he explained that these were really gas, and quite twothirds of the energy of radium was transferred to the gas which it emitted, which comes off at a regular rate, and this he pointed out raised the question as to how long radium would last. He replied for ever, as the amount of gas was always proportionate to the amount of radium present. He likened this emission ol gas to taking a slice of bread and cutting it in two, which operation say occupied a minute, and then cutting one half in two again, and so on continually cutting in two each successive half obtained. How long would it take him to cut the bread entirely up. He could never do it. He would always be halving to infinity, and the task would take him an eternity to perform. It was exactly tho same with radium. The amount of gas was always proportionate to the mass of radium existing and was always being produced. There was however, he remarked, one point easily defined. When would radium be half gone ? They had just measured it in his ( Sir William's ) laboratory and had found that it would take 1,750 years, so that anyone who invested in radium would retain at least one-half of the capital at the end of 1,750 years. The Austrian government some time entrusted him with about half a gramme or one fifty-fifth part of an ounce of radium for his private use. Its value was about £9. Less thau a year ago Dr. Gray had himself performed the experiment of isolating the Alpha emanation of radium, and they enclosed it in a fine glass tube, much finer than the finest thermometer tube that was ever made. They compressed it and liquefied it. In the latter stage it shone with a purplish light, although it was quite transparent like water. When reduced to a temperature of —GO deg. Cent, it solidified, and then it shone with an extremely brilliant light like a min iature electric arc light. The quan tity they used was extremely small, being less than the point of the finest needle, yet they ascertained its boil ing point, and its specific gravity.

Radium was the most concentrate.-' form of energy known. It is a sub stance which goes on changing other things to which various names have been given. These substinces were named radium A, radium B. radium C, and so on up to radium F. Some had a very brief existence, lasting only thirty or forty minuter,, and he had never seen them. He had seen radium D, which would he gone in about forty years.- This was a substance rather dull looking, like lead, and that was nearly all hs could say about it. There were other substances probably like polon'um which Madame Curie discovered. During these emanations radium rave a ;rcat deal of energy, generally manifested as light, but as a matter o' fact radium -kept itself hot ; there was a great deal of heat generated It could be calculated, and it war found that it gave off about 3,500,000 times as much heat a? would Ik given off by the oxyhydrogen blow pipe, which gave a temperature of over 2,000 deg. Cent. What did this energy do ? It sent out the Alpha rays at a velocity o about 40,000 miles per second, anc these particles naturally carried a great deal of energy. The Beta rays although only about one-thousandth part of the size, also carried tre mendons energy, owing to their enormous velocity, which exceeded tha' of the Alpha rays. They could de compose water and metallic substan ces, and hi these decompositions thc-3 found elements produced which the: did not imagine to exist in the substances so treated. For instance, ir decomposing ordinary copper sulphate they were surprised to discover 11th ium in what remained, and ro trecc: of the copper salt. He had repeated ;his experiment five times, a-.d the experiments were still going on.