Radium, its physics & therapeutics / by Dawson Turner.

Date:
1914
    tlmn uranium, and this body she set herself to isolate. Jhe only test she had for it was its radio-active power and the method she adopted was to endeavour by various chemical processes to separate from the ore the radio-active element. The process was a most laborious one, but ultimately a substance was obtained, though in very small quantities, which was two million times more active than uranium. At first only a tenth of a grain was obtained from 2 tons of the uranium on*, hut the German chemist Giesel afterwards suc- ceeded in extracting 4 grains from 1 ton of the best pitchblende, which is found in the celebrated Joa- chims thal mine in Austria (Fig. 4). The Austrian Government very generously aided the Curies by placing several tons of pitchblende at their disposal. 1 he new element extracted by the Curies was named Radium. It belongs to the group of the alkaline earths, and is closely allied to barium; its atomic weight was found to be 226, and its spectrum characteristic of the alkaline earths. The pure metal has recently been.isolated by Mine. Curie and M. Debieme. It is white in colour, altering rapidly in air, and actively decomposing water. Its chief salts are-the bromide, chloride, nitrate, sulphate, and carbonate; the first three are soluble, the last two are insoluble. When, therefore, we speak of pure radium, we mean the pure salt, and of these the bromide is the com- monest. Radio-active Substances.—The radio-active sub- stances separated, of reasonably slow period of trans-
    formation, are—uranium, thorium, radium, actinium, ionium, and radiolead (radium D). Of other radio-active substances of shorter life there are—polonium, radiothorium, mesothorium; in addition to these there are a large number of other substances like the radium emanation, radium A, B, C, Fn;. 4.—Pitchblende. thorium X. and many others, which have a period of transformation measured in days or weeks. These bodies are distinguished from such substances as radium by the difference in their period of trans- formation and in their chemical and physical pro- perties.
    KADIUM T'“ period of an emanation means the time re qeired for its activity to fall to half value. .ml th°f ‘T ,S"b8tances are o» high atomic weight third tr16, P'aCeS ra‘"'U"' in the of the wav Jrt . aV‘e9t 6lement: Uranium lading the next r rmC WeiBht 0f 238' and th°rium c°ming next with an atomic weight of 282 ^ act!veb.au;yf!hre are °‘her b°lii;S whi<* are -ho. th Tnt’nre to " °' “ «* found in he future to possess this property in some degree an ZZZPeHf “ UnaUerabIe - — unin- ' uiolecular combination. The dates which are important in this new line of research area^^: IV !'■ ‘diaooverod Iho cathode rays in 1870 rofaanr Rdntgon discovered the X ray. ta 80S II. H Becquerel ,1,.covered radio-activity i„ l89c I ho < unc, discovered radium in 1898. Wkd™nUtaeiW3d ,"'“l0 kn°W" hi“ th“°ry °f Characteristic Effects. The four characteristic effects of radio-active bodies cli 0 J;.Tbey “ffeCt sensitive Photographic plates in much the same manner as light. 2. They produce fluorescence — i.e., they cause Z 7 SUbfanCeS’ SUOh as bari- platinocyani^: and diamonds, to glow with a visible light. 3‘ rh<?y 10nize the air~»-e., they cause it to become * The salts of potassium and rubidium give off beta rays.
    a conductor of electricity, so that a body charged with electricity becomes discharged. 4. They produce heat. Some of their other effects are the emission of light, the decomposition of water and \arious gasts. the oxidation of metals in air—for this reason it is said that radium should not be preserved in an aluminium case, lest the case be eaten away by the oxidation (the writer has not observed this effect)— iodine is liberated from iodoform, glass and vitreous bodies are coloured violet, certain physiological and pathological effects are produced: these will be re- ferred to later. Chiefly from Professor Rutherford’s work we know that these effects are due to the rays and emanation which radio-active bodies give off. The rays are divided into three kinds, known respectively as alpha, beta, and gamma rays, and each of these demands careful consideration. The alpha rays are not really rays at all. hut are projectiles fired out by the radium as though it were a perpetual Maxim gun. A grain of radium bromide expels each second about ten thousand million alpha particles. They each carry two unit charges of posi- tive electricity, their mass is four times that of a hydrogen atom, their velocity is 9.000 to 13.000 miles per second, and there are conclusive reasons for believing either that they consist of helium or that they become converted into helium, that strange ineit element so long known to exist in the sun, but onU
    H HA DIMM i< (cully discovered on earth The u* a,,, , , . Lli< atomic wenrhf the alpha particle is the same as that of i r " f ** and Mr. spectrum of helium gradually appears in at I ■ U which only the emanation of radium has I " ^ mt° *• i<‘ ( ream of the alchemists fulfilled—there is , ran,s,,lutation of one element into another- th element radium has changed into the element helium the nobler into the baser metal and » . . ’ antithesis of a substance of absolutely negative properties and of verv small • . gatlve produced by a substa^e ^ltc^ether t^Triordii' Propel i ,es and of exceedingly high atomic weight Hut. this is what we might exrmnt • n g Zai„sen rf Un,i mT bUt iwrt ***** debris ™ . , lhere “r,J rea% kinds of alpha ravs distinguished from one another by their r lmr , tration- 11..f J tiieir range ot pene- tm .01, but they are relatively very easily sto n ed a single Sheet of notepaper will intercept then, and annnt,ating ^ °”'y gCt *hn'»«h » -eh,, tzz. ?n,tbn-—•»■» XI is Obvious that, even if the radium “Pfed d,r<,ctly '« the skin without any screen or .0 ective covering, the alpha rays will he stopped n onw T'mtrer °f ,he »nd therefore can o„, bl. used for ^ mQst "one A consequence of this is that it is rarelv -sUde to make any therapeutic use whatevT* these rays, and that is to he regretted, as 95 pe