RADIUM.
By Sir William Ramsay, K.C.B., F.R.S.
The strange qualities of radium, especially its brilliance in the dark and its power of illuminating some other bodies, attracts the attention of the entire world. This radium is, we believe, a metal, although till now it has not been produced in metallic form, for its salts are similar to the salts of barium, a white metal and a well-known element. The reason is that so little of these salts is available that it cannot be wasted in experimenting to effect the change from a salt into a metal, for the loss would be great. The best-known salt, the bromide, costs twelve shillings per milligram, an almost invisible quantity.
All metals have their peculiar spectra. If their salts be heated in a flame, on examining them by means of the spectroscope, coloured lines peculiar to each metal may be seen, which are named its "spectrum." Thus a metal is recognisable from its spectrum. Radium has its particular spectrum, which is like the spectrum of barium, but different in the location of the lines. We therefore believe that radium is an element similar to the other metals.
From the salts of radium a gas continually escapes, which has the quality of shining in the dark, remaining warm the while, and it throws out bodies known as electrons. When these bodies touch the air or any gas they impart to that gas the power to discharge an electroscope. While this gas is giving forth heat and discharging electrons it gradually vanishes, and instead another gas appears, of low density, the spectrum of which M. Janssen, a famous French astronomer, noticed in the light of the sun during 1868, and which was first discovered on the earth by the writer of this article.
It seems, therefore, that one element, radium, can produce another—namely, helium. Whether, as is possible, other elements are formed at the same time we do not know. That question remains for further investigation.
Let us see whether radium possesses any properties, differing in kind or in degree, from those of other elements which have not yet been observed to undergo any such extraordinary change.
First, then, there are, at least, other two elements which discharge electrons. These are thorium and uranium. They all, as well as radium, undoubtedly consist of atoms of great weight. If we take the weight of an atom of hydrogen as unity, that of radium weighs about 225 (or perhaps even more); that of thorium 232, and that of uranium 240.
As these are the three heaviest kinds of atoms known, we may guess that when an atom possesses a great mass it tends towards disruption; that just as no star has been seen possessing a magnitude greater, let us say, than one thousand times that of our sun (else it would be unstable, and would throw off satellites), so no elements of a greater atomic weight than a certain maximum can exist, and that those which we know to possess very high atomic weights are themselves in the process of throwing off satellites.
It is perhaps permissible to speculate that electrons are small satellites, and that atoms of helium are larger ones. But to pursue the subject further, without more definite knowledge, which can be gained only by experiment, would be unprofitable.
Needless to say, many workers are doing their utmost to penetrate more deeply into this most interesting field of exploration.
La Leono kaj la Bovoj.—Tri bovoj sin paŝtis sur herbejo, tre pace kaj amike. Leono jam de longe estis rigardinta ilin kun la espero je kapti ilin, sed sentis ke ne estos ŝanco por tion fari, dum ili kune restados.
Tial li sekrete ekdissemis malbonajn kaj falsajn dirojn pri unu kontraŭ la aliaj, ĝis tio naskis ĵaluzon kaj malfidon inter ili. Tuj kiam la leono vidis ke ili evitis unu la aliajn kaj sin paŝtis malkune, li sin ĵetis sur ĉiun aparte, kaj tiel sukcesis ke ĉiu el ili fariĝis facila kaptaĵo de la leono.
Kiam amikoj malpacas, malamikoj profitas.
(6266).
La Rano kaj la Bovo.—Bovo sin paŝtis en marĉejo kaj okazis premi sian piedegon inter kelke da ranidoj, kaj morte premegis unu el la kovitaro[1]. Postvivanta ranido forkuris al la patrino por sciigi al ŝi la teruran novaĵon.—"Kaj, ho patrino, estas tre granda besto, granda kvarkrura[2] besto kiu tion faris!"—"Tre granda?" diris la maljuna ranino. "Kiel granda? Ĉu ĝi estas tiel dika" (kaj ŝi ŝveligis sin multe) "tiel dika kiel tio?"—"Ho!" diris la ranideto, "multe pli dika ol tio."—"Nu, ĉu ĝi estas tiel granda?" (kaj ŝi ŝveligis sin ankoraŭ plie)—"Certe, patrino, ĝi estas; kaj, eĉ se vi krevigos[3] vin, vi neniam atingos la duonon de ĝia dikeco."
La maljuna ranino, kolerante ke ŝia povo tiel estas dubata, alian penadon faris kaj vere krevis.
"Sin tro ŝveligi estas danĝere."
(6266).
FOOTNOTES:
[1] Brood.
[2] Fourlegged.
[3] Burst.