Chemistry and Physics. 361 



fourth blue band (2d order), 4213-5; fifth blue band (1st order), 

 about 3878. The red pair of argon lines were also faintly visible. 

 The density of this gas, determined as before, was 19*87, not 

 differing sensibly from that of argon. On determining the ratio 

 of specific heats for this new gas, it was found to be 1*660; thus 

 showing that it is monatomic like neon. From the fact that, both 

 in its spectrum, and in its behavior at low temperatures, this gas 

 differs very markedly from argon, the authors regard it as a dis- 

 tinct elementary substance and propose for it the name " met- 

 argon " y suggesting that it stands to argon as nickel does to 

 cobalt, having approximately the same atomic mass but different 

 properties. The reason that krypton does not appear in the 

 higher fraction of argon, the authors explain by the fact first, 

 that to prepare it, the manipulation of no less than 60000 times 

 the volume of the impure sample they obtained, was required ; 

 and second, that while metargon is a solid at the temperature of 

 boiling air, krypton is probably a liquid and so more volatile. 

 Moreover the liquid air from which the krypton had been ob- 

 tained had been previously filtered. — Chem. News, lxxviii, 1, July, 

 1898; C. B., cxxvi, 1762, June, 1898. G. r. b. 



2. On Metargon. — It has been pointed out by Dewar that on 

 liquefying a sample of argon obtained from Lord Rayleigh, about 

 250 cc in volume, contained in a bulb with a quill tube attach- 

 ment, by immersion in liquid air, it always yields a perfectly clear 

 liquid free from turbidity or opalescence. Since very small frac- 

 tions of a per cent of impurity in a gaseous substance, separating 

 as a solid, can be readily detected in this way, for example the 

 0*04 per cent of carbon dioxide in dry air or 0*1 per cent of chlo- 

 rine in oxygen, it is remarkable that one per cent of a gas giving 

 a white solid at the temperature of liquid air, could escape detec- 

 tion if it existed in the sample of argon furnished by Lord Ray- 

 leigh. — Chem. News, lxxviii, 70, August, 1898. g. f. b. 



3. On the Density and Boiling Point of liquid Hydrogen. — 

 At the meeting of the Chemical Society on June 2d, Dewar gave 

 further facts concerning liquid hydrogen. Its boiling point in 

 air determined by a platinum resistance thermometer was found 

 to be 35° absolute or —238° C; a value higher by about 17 per 

 cent than the value which Olszewski obtained by adiabatic expan- 

 sion. Since its critical point must be about 50° absolute, the 

 whole range of liquid hydrogen is only about 50° absolute. 

 Hence there can be only a few degrees + or — difference in the 

 estimates of the boiling point deduced from theory ; though in 

 fact this is a large percentage of the whole, the range being so 

 small. Hence we may predict almost certainly that with no con- 

 ceivable means at our present command, shall we ever be able to 

 get nearer the absolute zero than —250° C, or say + 20° absolute. 

 In other words, the practical fall in temperature given by liquid 

 hydrogen under high exhaustion will never exceed 10° or 15° 

 below the present boiling point. As to its density, since it ap- 

 pears as a transparent liquid, having a well-defined meniscus, 



