BERYLLIUM: 4 funnels of 40 atoms 160 Central globe 4 ---- Total 164 ---- Atomic weight 9.01 Number weight 164/18 9.11 CALCIUM (Plate VIII, 2) shows in each funnel three contained spheres, of which the central one has within it seven ovoids identical with those of beryllium, and the spheres above and below it contain each five ovoids (7 _b_) in which the three contained spheres have, respectively, two, five, and two atoms. The central globe is double, globe within globe, and is divided into eight segments, radiating from the centre like an orange; the internal part of the segment belonging to the inner globe has a triangular body within it, containing four atoms (7 _c_), and the external part, belonging to the encircling globe, shows the familiar "cigar" (7 _d_). In this way 720 atoms are packed into the simple beryllium type. CALCIUM: 4 funnels of 160 atoms 640 Central globe 80 ---- Total 720 ---- Atomic weight 39.74 Number weight 720/18 40.00 STRONTIUM (Plate VIII, 3) shows a still further complication within the funnels, no less than eight spheres being found within each. Each of the highest pair contains four subsidiary spheres, with five, seven, seven, five atoms, respectively (7 _e_, _g_, _f_). The _g_ groups are identical with those in gold, but difference of pressure makes the containing body spherical instead of ovoid; similar groups are seen in the top ring of the iodine funnel, where also the "hole" is ovoid in form. The second pair of spheres contains ten ovoids (7 _b_) identical with those of calcium. The third pair contains fourteen ovoids (7 _a_) identical with those of beryllium, while the fourth pair repeats the second, with the ovoids re-arranged. The internal divisions of the double sphere of the central globe are the same as in calcium, but the contents differ. The "cigars" in the external segments are replaced by seven-atomed ovoids (7 _h_)--the iodine ovoids--and the external segments contain five-atomed triangles (7 _i_). Thus 1,568 atoms have been packed into the beryllium type, and our wonder is again aroused by the ingenuity with which a type is preserved while it is adapted to new conditions. STRONTIUM: 4 funnels of 368 atoms 1472 Central globe 96 ---- Total 1568 ---- Atomic weight 86.95 Number weight 1568/18 87.11 The corresponding group, headed by oxygen--oxygen, chromium, molybdenum, wolfram and uranium--offers us another problem in its first member.