.
| N | 40 | 42 | 44 | 46 | 47 | 50 | 51 | 57 |
| 4.6 | 5.5 | 6.1 | 6.6 | 6.9 | 8.4 | 9.0 | 11.6 | |
| 4.93 | 5.53 | 6.17 | 6.84 | 7.19 | 8.29 | 8.67 | 11.21 |
It is seen that the agreement is close, and probably within the limits of experimental error. A comparison with the second relation is not possible at present, and we meet also here with a difficulty arising from the fact that Moseley observed a greater number of lines in the
radiation than should be expected on Kossel’s simple scheme[33].
There is another point in connexion with the above considerations which appears to be of interest. In a recent paper W. H. Bragg[34] has shown that, in order to excite any line of the
radiation of an element, the frequency of the exciting radiation must be greater than the frequency of all the lines in the