SODIUM (Plate VI, 2) has been already described (p. 349, January), as a type of the group, so we need only refer to its internal arrangement in order to note that it is the simplest of the dumb-bell group. Its twelve funnels show only four enclosed bodies, the same as we see in chlorine, bromine, iodine, copper and silver, and which is very little modified in gold. Its central globe is the simplest of all, as is its connecting rod.

We may therefore take it that sodium is the ground-plan of the whole group.

SODIUM: Upper part { 12 funnels of 16 each 192 { Central globe 10 Lower part same 202 Connecting rod 14 ---- Total 418 ---- Atomic weight 23.88 Number weight 418/19 23.22 COPPER (Plate VI, 3) introduces an addition in the funnel, that we shall find elsewhere, _e.g._, in silver, gold, iron, platinum, zinc, tin, the triangular arrangement near the mouth of the funnel and adds to the ten atoms in this nineteen more in three additional enclosed bodies, thus raising the number of atoms in a funnel from the sixteen of sodium to forty-five. The number in the central globe is doubled, and we meet for the first time the peculiar cigar or prism-shaped six-atomed arrangement, that is one of the most common of atomic groups. It ought to imply some definite quality, with its continual recurrence. The central column is the three, four, five, four, three, arrangement already noted.

COPPER: Upper part {12 funnels of 45 atoms 540 {Central globe 20 Lower part same 560 Connecting rod 19 ---- Total 1139 ---- Atomic weight 63.12 Number weight 1139/18 63.277 SILVER (Plate VI, 4) follows copper in the const.i.tution of five of the bodies enclosed in the funnels. But the triangular group contains twenty-one atoms as against ten, and three ovoids, each containing three bodies with eleven atoms, raise the number of atoms in a funnel to seventy-nine. The central globe is decreased by five, and the prisms have disappeared. The connecting rod is unaltered.

SILVER: Upper part {12 funnels of 79 atoms 948 {Central globe 15 Lower part same 963 Connecting rod 19 ---- Total 1945 ---- Atomic weight 107.93 Number weight 1945/18 108.055 (This atomic weight is given by Stas, in _Nature_, August 29, 1907, but it has been argued later that the weight should not be above 107.883.)

[Ill.u.s.tration: PLATE VII.]

GOLD (Plate VII) is so complicated that it demands a whole plate to itself.

It is difficult to recognize the familiar dumb-bell in this elongated egg, but when we come to examine it, the characteristic groupings appear. The egg is the enormously swollen connecting rod, and the upper and lower parts with their central globes are the almond-like projections above and below, with the central ovoid. Round each almond is a shadowy funnel (not drawn in the diagram), and within the almond is the collection of bodies shown in _e_, wherein the two lowest bodies are the same as in every other member of the negative and positive groups; the third, ascending, is a very slight modification of the other thirds; the fourth is a union and re-arrangement of the fourth and fifth; the fifth, of four ovoids, adds one to the three ovoids of bromine, iodine and silver; the triangular group is like that in copper and silver, though with 28 atoms instead of 10 or 21, and it may be noted that the cone in iron has also 28. The central body in the ovoid is very complicated, and is shown in _c_, the bodies on each side, _d_, are each made up of two tetrahedra, one with four six-atomed prisms at its angles, and the other with four spheres, a pair with four atoms and a pair with three. We then come to the connecting rod. One of the four similar groups in the centre is enlarged in _a_, and one of the sixteen circling groups is enlarged in b. These groups are arranged in two planes inclined to one another.

GOLD: Upper part { 12 funnels of 97 atoms 1164 { Central ovoid {c 101 {2 d, 38 76 Lower part same 1341 Connecting rod { 4 a 84 336 {16 b 33 528 ---- Total 3546 ---- Atomic weight 195.74 Number weight 3546/18 197 It may be noted that the connecting rod is made up of exactly sixteen atoms of occultum, and that sixteen such atoms contain 864 ultimate atoms, the exact member of atoms in t.i.tanium.

III.

Occultum was observed by us in 1895, and, finding that it was so light, and so simple in its composition, we thought that it might be helium, of which we were unable, at the time, to obtain a sample. When, however, helium itself came under observation in 1907, it proved to be quite different from the object before observed, so we dubbed the unrecognised object Occultum, until orthodox science shall find it and label it in proper fashion.

OCCULTUM (Plate VI, 1).

We here meet the tetrahedron for the first time, with each angle occupied by a six-atomed group, the atoms arranged as on the end triangles of a prism. This form recurs very often, and was noted, last month, as seen in copper (Plate VI, 3); it revolves with extreme rapidity around its longitudinal axis, and looks like a pencil sharpened at both ends, or a cigar tapering at both ends; we habitually spoke of it as "the cigar." It appears to be strongly coherent, for, as will be seen below, its six atoms remain attached to each other as meta-compounds and even when divided into two triplets as hyper-compounds, they revolve round each other.

Above the tetrahedron is a balloon-shaped figure, apparently drawn into shape by the attraction of the tetrahedron. The body below the tetrahedron looks like a coil of rope, and contains fifteen atoms; they are arranged on a slanting disk in a flat ring, and the force goes in at the top of one atom, and out of the bottom of it into the top of the next, and so on, making a closed circuit. The two little spheres, each containing a triplet, are like fill-up paragraphs to a compositor--they seem to be kept standing and popped in where wanted. The sphere marked _x_ is a proto-compound, the balloon when set free.

As was noted under gold (p. 41), sixteen occultum bodies, re-arranged, make up the connecting rod in gold:--

OCCULTUM: Tetrahedron 24 Balloon 9 Triplets 6 Rope-circle 15 ---- Total 54 ---- Atomic weight Not known Number weight 54/18 3 DISSOCIATION OF ATOMS.

Before proceeding to the study of other chemical atoms, as to their general internal arrangements, it is desirable to follow out, in those already shown, the way in which these atoms break up into simpler forms, yielding successively what we have called proto-, meta-, and hyper-compounds. It is naturally easier to follow these in the simpler atoms than in the more complex, and if the earlier dissociations are shown, the latter can be more readily and more intelligibly described.

The first thing that happens on removing a gaseous atom from its "hole"

(see pp. 21 to 23) or encircling "wall," is that the contained bodies are set free, and, evidently released from tremendous pressure, a.s.sume spherical or ovoid forms, the atoms within each re-arranging themselves, more or less, within the new "hole" or "wall." The figures are, of course, three-dimensional, and often remind one of crystals; tetrahedral, octagonal, and other like forms being of constant occurrence. In the diagrams of the proto-compounds, the const.i.tuent atoms are shown by dots.

In the diagrams of the meta-compounds the dot becomes a heart, in order to show the resultants of the lines of force. In the diagrams of the hyper-compounds the same plan is followed. The letters _a_, _b_, _c_, &c., enable the student to follow the breaking up of each group through its successive stages.

HYDROGEN (Plate V, 1).

[Ill.u.s.tration]

The six bodies contained in the gaseous atom instantaneously re-arrange themselves within two spheres; the two linear triplets unite with one triangular triplet, holding to each other relative positions which, if connected by three right lines, would form a triangle with a triplet at each angle; the remaining three triangular triplets similarly arrange themselves in the second sphere. These form the proto-compounds of hydrogen.

In the dissociation of these, each group breaks up into two, the two linear triplets joining each other and setting free their triangular comrade, while two of the triangular triplets similarly remain together, casting out the third, so that hydrogen yields four meta-compounds.

In the hyper-condition, the connexion between the double triplets is broken, and they become four independent groups, two like ix, in the hyper-types (p. 25), and two remaining linear, but rearranging their internal relations; the two remaining groups break up into two pairs and a unit.

The final dissociation sets all the atoms free.

OCCULTUM (Plate VI, 1).

[Ill.u.s.tration]

On the first dissociation of the component parts of occultum, the tetrahedron separates as a whole, with its four "cigars," flattening itself out within its hole, _a_; two "cigars" are positive and two negative, marked respectively _a_ and _a'_. The rope becomes a ring within a sphere, _b_, and the two bodies _d_ _d_, which are loose in the gaseous atom, come within this ring. The balloon becomes a sphere.

On further dissociation, the "cigars" go off independently, showing two types, and these again each divide into triplets, as meta-compounds. _B_, on the meta-level, casts out the two _d_ bodies, which become independent triplets, and the "rope" breaks into two, a close ring of seven atoms and a double cross of eight. These subdivide again to form hyper-compounds, the ring yielding a quintet and a pair, and the double cross separating into its two parts.

The balloon, _c_, becomes much divided, the cohesion of its parts being slight; it forms two triplets, a pair and a unit, and these set free, on further dissociation, no less than five separate atoms and two duads.

The two triplets of _d_ each cast out an atom on dissociation, and form two pairs and two units.

SODIUM (Plate VI, 2).

It is convenient to consider sodium next, because it is the basic pattern on which not only copper, silver and gold are formed, but also chlorine, bromine and iodine.

[Ill.u.s.tration]

When sodium is set free from its gaseous condition, it divides up into thirty-one bodies--twenty-four separate funnels, four bodies derived from the two central globes, and three from the connecting rod. The funnels become spheres, and each contains four enclosed spheres, with more or less complicated contents. Each central globe yields a s.e.xtet and a quartet, and the rod sets free two quartets and a peculiarly formed s.e.xtet.

When the proto-compounds are dissociated, the funnel-sphere sets free: (1) the contents of _a_, rearranged into two groups of four within a common sphere; the sphere yields four duads as hyper-compounds; (2) the contents of _b_, which unite themselves into a quartet, yielding two duads as hyper-compounds; and (3) the contents of the two spheres, _c_, which maintain their separation as meta-compounds, and become entirely independent, the atoms within the sphere revolving round each other, but the spheres ceasing their revolution round a common axis, and going off in different directions. The atoms break off from each other, and gyrate in independent solitude as hyper-"compounds." Thus each funnel yields finally ten hyper-bodies.

The part of the central globe, marked _d_, with its six atoms, whirling round a common centre, becomes two triplets, at the meta-stage, preparing for the complete separation of these as hyper-bodies. The second part of the same globe, marked _e_, a whirling cross, with an atom at each point, becomes a quartet in the meta-state, in which three atoms revolve round a fourth, and in the hyper-state this central atom is set free, leaving a triplet and a unit.

Each of the two bodies marked _f_, liberated from the connecting rod, shows four atoms whirling round a common centre, exactly resembling _e_ in appearance; but there must be some difference of inner relations, for, in the meta-state, they re-arrange themselves as two pairs, and divide into two as hyper-bodies.

The body marked _g_ is a four-sided pyramid, with two closely joined atoms at its apex; these still cling to each in mutual revolution as a meta-body, encircled by a ring of four, and this leads to a further dissociation into three pairs on the hyper-level.

CHLORINE (Plate V, 2).

[Ill.u.s.tration]

The description of the funnel of sodium applies to that of chlorine, until we come to the body nearest the mouth, the sphere containing three additional bodies; this remains within the funnel in the first dissociation, so that again we have twenty-four separate funnels as proto-compounds; the central globes are the same as in sodium, and yield the same four bodies; the connecting rod sets free five bodies, of which two are the same; we have thus thirty-three separate bodies as the result of the dissociation of chlorine into its proto-compounds. As all the compounds which are in sodium break up in the same way into meta- and hyper-compounds, we need not repeat the process here. We have only to consider the new meta- and hyper-compounds of the highest sphere within the funnel, and the two triplets and one quintet from the connecting rod.

The additional body within the proto-funnel is of a very simple character, three contained triangles within the flattened sphere. On release from the funnel, on the meta-level, the atoms rearrange themselves in a whirling set of three triplets, and these break off from each other as hyper-compounds.

The two triplets from the connecting rod, also, are of the simplest character and need not delay us. The five-atomed body, a four-sided pyramid as a proto-compound, becomes a ring whirling round a centre on the meta, and two pairs with a unit on the hyper.

BROMINE (Plate V, 3).

Three additional bodies appear at the top of the funnel, which otherwise repeats that of chlorine. The connecting rod is the same and may be disregarded. The central globes become more complex. The additions are, however, of very easy types, and hence are readily dealt with. Each of the three similar ovoid bodies contains two triplets--each a triangle and a quintet--a four-sided pyramid. These are the same, as may be seen in the connecting rod of chlorine, and we need not repeat them. Only the globe remains. This does not break up as a proto-compound but is merely set free, _a_ and the 2 _bs_ whirling in a plane vertical to the paper and the two smaller bodies, _cc_, whirling on a plane at right angles to the other.

These two disengage themselves, forming a quartet as a meta-compound, while _a_ makes a whirling cross and _bb_ a single s.e.xtet; these further dissociate themselves into four pairs and two triplets.

IODINE (Plate V, 4).

[Ill.u.s.tration]

Iodine has nothing new to give us, except five similar ovoid bodies at the top of each funnel, and two quartets instead of two pairs in the central globe. The ovoid bodies become spheres when the funnels are thrown off, and a crystalline form is indicated within the sphere. The atoms are arranged in two tetrahedra with a common apex, and the relationship is maintained in the meta-body, a septet. The latter breaks up into two triplets and a unit on the hyper-level. In the central globes, the _a_ of bromine is repeated twice instead of the pairs in _cc_.

COPPER (Plate VI, 3).