Radium Reveals Properties Unknown Till Now.
While radio-activity may be a universal property of matter, to be disclosed more and more as means of detection are refined and improved, radium compounds are to-day in a class quite by themselves. Radium bromide constantly maintains itself at a temperature of 3° to 5° C. higher than that of its surroundings, so that every hour it could boil its own weight of water. Professor Rutherford estimates the life of radium as 1,800 years, its emanations in breaking up through their successive stages emitting about three million times as much energy as is given out by the union of an equal volume of hydrogen and oxygen, mixed in the proportions which form water, a union accompanied by more heat than that evolved in any other chemical change. Whence this amazing stream of energy? It is probable that each radium atom may break into minute parts, or corpuscles, which, moving at a velocity of 120,000 miles a second or so, collide so as to cause the observed heat.
From another side the compounds of radium bid us revise the laws of chemical change as taught up to the close of the nineteenth century. In the pores of many radio-active minerals may be found that remarkable element, helium, first detected in the sun by means of the spectroscope, then afterward discovered in the pores of cleveite, a mineral unearthed in Norway. Sir William Ramsay and Mr. Frederick Soddy have found helium in the gases evolved from radium chloride kept as a solid for some months. The spectrum of helium was at first invisible; it soon appeared and steadily grew more intense with the lapse of time. “It appears not unlikely,” says Professor Rutherford, “that many of the so-called chemical elements may prove to be compounds of helium, or, in other words, that the helium atom is one of the secondary units with which the heavier atoms are built up.”[21]
[21] Ernest Rutherford “Radio-activity.” Second edition. New York: Macmillan Co.; Cambridge, England, University Press, 1905.
Photograph by Rice, Montreal.
PROFESSOR ERNEST RUTHERFORD,
McGill University, Montreal.
Already the phenomena of radio-activity, although of puzzling intricacy, have greatly broadened our conceptions of matter. Where we were wont to deem it of simple structure, it displays a baffling complexity, as indeed has long been suggested in so highly diversified a spectrum as that of iron. We find that radiations from an “element” may consist not only in the undulations of an ether, but also in an emission of matter as real as the projection of steam from a boiling pot. Newton believed sunshine to be a stream of corpuscles: he was wrong with respect to sunlight, his conception is true of many other kinds of radiation. Until quite lately we looked upon atoms as indivisible bodies; to-day we have learned that at least some of them may on occasion divide into many parts, each part moving with a speed approaching that of light, with energy far exceeding that of any chemical action we know. In the field of ray-transmission our knowledge has undergone a like gain in width. Twenty years ago we spoke of the opacity of lead, the transparency of flint glass, as absolute properties. To-day we learn that given its accordant ray any substance whatever affords that ray free passage, as when oak an inch thick transmits pulses from radium. Yet more: ordinary chemical changes require us to bring one substance into contact with another; usually we must also apply heat or electricity to the bodies thus joined; they are always responsive to changes of temperature. Within the past six years we have become acquainted with changes incomparably more energetic than those of the most violent chemical action; many of them proceed with apparent spontaneity from a substance all by itself. In the case of radium neither extreme cold nor extreme heat has any perceptible effect upon the radiant stream.
One of the results of investigation in radio-activity is that it shows the alchemists in their attempts at transmutation to have stood on solid ground. Says Professor Rutherford: “There can be no doubt that in the radio-elements we are witnessing the spontaneous transformation of matter, and that the different products which arise mark the stages or halting places in the process of transformation, where the atoms are able to exist for a short time before breaking up into new systems.”