+--------+-----------+----------+----------+----------+----------+----------+----------+----------------------------+ |He 4.0 |Li 7.03 |Be 9.1 |B 11.0 |C 12.00 |N 14.01 |O 16.00 |F 19.0 | .. .. .. | | Ne 20 | Na 23.00 | Mg 24.32| Al 27.1 | Si 28.4 | P 31.0 | S 32.06 | Cl 35.45| .. .. .. | |Ar 39.9 |K 39.15 |Ca 40.1 |Sc 44.1 |Ti 48.1 |V 51.2 |Cr 52.0 |Mn 55.0 |Fe 55.9, Ni 58.7, Co 59.0 | | .. | Cu 63.6 | In 65.4 | Ga 70 | Ge 72.5 | As 75.0 | Se 79.2 | Br 79.96| .. .. .. | |Kr 83.0 |Rb 85.5 |Sr 87.6 |Y 89.0 |Zr 90.6 |Cb(Nb) 94 |Mo 96.0 | .. |Ru 101.7, Rh 103.0, Pd 106.5| | .. | Ag 107.93| Cd 112.4| In 115 | Sn 119.0| Sb 120.2| Te 127.6| I 126.97| .. .. .. | |Xe 130.7|Cs 132.9 |Ba 137.4 |La 138.9 |Ce &c. 140|Ta 181 |W 184 | .. |Os 191, Ir 193.0, Pt 194.8 | | .. | Au 197.2 | Hg 200.0| Tl 204.1| Pb 206.9| Bi 208.0| .. | .. | .. .. .. | | .. | .. |Ra 225 | .. |Th 232.5 | .. |U 238.5 | .. | .. .. .. | +--------+-----------+----------+----------+----------+----------+----------+----------+----------------------------+ But upon closer investigation it must be confessed that these regularities can be called only rules, and not laws. In the first line one would expect that the steps in the values of the atomic weights should be regular, but it is not so. There are even cases when it is necessary to invert the order of the atomic weights to satisfy the chemical necessities. Thus argon has a larger number than potassium, but must precede it to fit into its proper place. The same is true of tellurium and iodine. It looks as if the real elements were scattered somewhat haphazard on a regular table, or as if some independent factor were active to disturb an existing regularity. It may be that the new facts mentioned above will lead also to an explanation of these irregularities; at present we must recognize them and not try to explain them away. Such considerations have to be kept in mind especially in regard to the very numerous attempts to express the series of combining weights in a mathematical form. In several cases rather surprising agreements were found, but never without exception. It looks as if some very important factor regulating the whole matter is still unknown, and before this has been elucidated no satisfactory treatment of the matter is possible. It seems therefore premature to enter into the details of these speculations. Transmutation of elements.