X.

VI.—The Star Groups.

We have now reached the last of the groups as arranged on Sir William Crookes' lemniscates, that forming the "neutral" column; it is headed by helium, which is sui generis. The remainder are in the form of a flat star (see Plate IV, 4), with a centre formed of five intersecting and "cigar"-bearing tetrahedra, and six radiating arms. Ten of these have been observed, five pairs in which the second member differs but slightly from the first; they are: Neon, Meta-neon; Argon, Metargon; Krypton, Meta-krypton; Xenon, Meta-xenon; Kalon, Meta-kalon; the last pair and the meta forms are not yet discovered by chemists. These all show the presence of a periodic law; taking an arm of the star in each of the five pairs, we find the number of atoms to be as follows:—

40 99 224 363 489 47 106 231 370 496

It will be observed that the meta form in each case shows seven more atoms than its fellow.

HELIUM: Two tetrahedra of 24 atoms 48 Two triangles of 9 atoms 18 Central egg 6 ---- Total 72 ---- Atomic weight 3.94 Number weight 72/18 4.00

NEON: Six arms of 40 atoms 240 Central tetrahedra 120

---- Total 360 ---- Atomic weight 19.90 Number weight 360/18 20.00

META-NEON: Six arms of 47 atoms 282 Central tetrahedra 120 ---- Total 402 ---- Atomic weight ---- Number weight 402/18 22.33

ARGON: Six arms of 99 atoms 594 Central tetrahedra 120 ---- Total 714 ---- Atomic weight 39.60 Number weight 714/18 39.66

METARGON: Six arms of 106 atoms 636 Central tetrahedra 120 ---- Total 756 ---- Atomic weight ---- Number weight 756/18 42

KRYPTON: Six arms of 224 atoms 1344 Central tetrahedra 120 ----- Total 1464 ----- Atomic weight 81.20 Number weight 1464/18 81.33

META-KRYPTON: Six arms of 231 atoms 1386 Central tetrahedra 120 ----- Total 1506 ----- Atomic weight ----- Number weight 1506/18 83.66

XENON: Six arms of 363 atoms 2178 Central tetrahedra 120 ----- Total 2298 ----- Atomic weight 127.10 Number weight 2298/18 127.66

META-XENON: Six arms of 370 atoms 2220 Central tetrahedra 120 ----- Total 2340 ----- Atomic weight ----- Number weight 2340/18 130

KALON: Six arms of 489 atoms 2934 Central tetrahedra 120 ---- Total 3054 ---- Atomic weight ---- Number weight 3054/18 169.66

META-KALON: Six arms of 496 atoms 2976 Central tetrahedra 120 ---- Total 3096 ---- Atomic weight ---- Number weight 3096/18 172

Only a few atoms of kalon and meta-kalon have been found in the air of a fair-sized room.

It does not seem worth while to break up these elements, for their component parts are so familiar. The complicated groups—a 110, b 63 and c 120—have all been fully dealt with in preceding pages.

There remains now only radium, of the elements which we have, so far, examined, and that will be now described and will bring to an end this series of observations. A piece of close and detailed work of this kind, although necessarily imperfect, will have its value in the future, when science along its own lines shall have confirmed these researches.

It will have been observed that our weights, obtained by counting, are almost invariably slightly in excess of the orthodox ones: it is interesting that in the latest report of the International Commission (November 13, 1907), printed in the Proceedings of the Chemical Society of London, Vol. XXIV, No. 33, and issued on January 25, 1908, the weight of hydrogen is now taken at 1.008 instead of at 1. This would slightly raise all the orthodox weights; thus aluminium rises from 26.91 to 27.1, antimony from 119.34 to 120.2, and so on.