264 Scientific Intelligence. 
diminished by removal of a heavier admixture, rather than 
increased by removal of a lighter one. 
Such are the problems which now confront us. Until more 
experiments have thrown further light on the subject, we regard 
it as labor lost to discuss the relations of these curious elements 
to others which find their proper place in the periodic table.— 
Nature, July 25, Aug. 1. 
2. Argonand Helium in Meteoric Iron.—Professor W. Ramsay, 
extending his researches upon the new element argon, has proved 
that it exists with helium in meteoric iron. The meteorite 
investigated was that of Augusta county, Virginia, two ounces of 
which, heated to redness in a hard glass tube, yielded 45 c.c. of 
gas. This appeared to consist chiefly of hydrogen, but after it 
had been exploded with oxygen, and the carbon dioxide and 
excess of oxygen absorbed, a residue of half a cubic centimeter 
was obtained. Several vacuum tubes having been filled with this 
after being dried, spectroscopic examination proved it to be for 
the most part argon, the trace of nitrogen which first appeared 
rapidly disappearing. All the argon lines were observed and 
also, faintly, the yellow D, of helium? A comparison of the 
spectrum with that of the helium from cleveite showed the 
presence of the red, blue-green, blue and violet lines characteristic 
of it. From quantitative observations with a mixture of argon 
and helium it is concluded that the latter element. makes up less 
than 10 p. ¢. of the gases obtained from the meteoric iron. 
Nature, lii, 224. 
3. The physical properties of Argon.—Lorp RAYLEIGH gives 
the following determination of the density of argon (O, = 16): 
19°940 
This result was obtained with the gas prepared from atmospherie 
air with the aid of oxygen and alkali only, and employing large 
quantities (two liters at 0°). It agrees almost exactly with the 
determination of Professor Ramsay made upon a relatively small 
amount and with gas derived from magnesium. In spite of its 
greater density the refraction. (#—1) of argon is only 0:961 
of that of air. Hence if for air under standard conditions, 
f= 10002923, we have for argon 
pt = 1:000281. 
— Nature, lii, 293. : 
4. The Fluorescence of Argon.—M. BrerRtHEtor has carried on, 
in conjunction with M. Deslandres, a series of careful experi- 
ments on the fluorescence of argon which accompanies its com- 
bination with benzene under the influence of the silent discharge ; 
this it appears is accomplished with the help of mercury in the 
form of a volatile compound. The effect at first is feeble and 
only to be observed in a*dark room, but after some fifteen hours a 
brilliant emerald fluorescence is obtained, visible in broad day- 
light and indeed more intense than that given by any other 
known gas. The wave lengths of the lines given in the photo- 
graphs are: 579, 577 and 546; 436, 405, 313, 312 (ultra-violet) ; 
also two violet lines besides, 420 and 416, scarcely visible, and 
