The Gold Deposits of Mount Morgan, Queensland. •"> H 



— 186.9° C. ; it freezes to an ice-like mass at — 191 ', and melts al 

 —189.6°. In its behaviour at low temperatures it stands between 

 oxygen and nitrogen, whose critical temperatures are — 118° and I Hi 

 respectively, and whose boiling points are — 1S2.7 and —194. I . 



Chemically, argon appears to be more inert than nitrogen, all 

 attempts to induce chemical action with even the most active sub- 

 stances having proved abortive. 



The facts so far obtainable do not warrant a final decision in regard 

 to its simplicity. If not an element, it is a mixture. There is evidence 

 on both sides, but the balance seems to be in favor of simplicity. Not 

 only does argon appear to be a single elementary substance, but its 

 molecules are apparently of simplest possible structure. A determina- 

 tion of the ratio of its specific heats at constant volume and constant 

 pressure points to the conclusion that its molecules are monatomic, 

 i. e., composed of a single atom each, instead of two atoms, as is the 

 case in almost all elementary gases and vapors. 



Certain very interesting and important theoretical issues are raised 

 by this conclusion. In connection with the density which the gas has, 

 it indicates an atomic weight of 40. But in this case there is no place 

 for the new element in the tables of Mendeleieff, which express the 

 periodic law, and which have been so generally accepted. If argon 

 should turn out to be a mixture, the difficulty may dissappear, but if 

 its simple character is finally demonstrated, an awkward dilemma is 

 offered between the validity of the periodic law and that of the con- 

 clusions drawn from the determinations of specific heat ratios. The 

 periodic law of Mendeleieff is, after all, as Professor Rucker has said, 

 "an empirical law, which rests on no dynamical foundation." The 

 present situation will strengthen many chemists in their feeling that, 

 although the law is a generalization which has in it many elements of 

 truth, and has hence proved of much value to chemistry, it is by no 

 means a complete or final expression of the relations of the elements. 



The diseovery of argon is a brilliant achievement. As Professor 

 Crookes said before reading his paper on the spectra of argon, " Here 

 we have a new chemical element, the principal properties of which 

 seem to be the negation of all chemical properties. Chemists will 

 understand how difficult it is to deal with anything which forms no 

 compounds and unites with nothing. The discovery commenced by a 

 prediction, followed after an interval by realization. . . . The 

 prediction and discovery of argon are only equalled by the few 

 discoveries . . . made . . . by the careful study of the periodic- 

 law, and to surpass it we must go baek to the predicted existence and 

 subsequent discovery of an unknown planet by Adams and Leverrier. " 

 — THE Nation. 



