710 



Mr. H. Gr. J. Moseley on the 

 Table II. 



a line. Q.j. 



\XlO s cm. 



N. 

 Atomic 

 Number. 



(3 line, j line. 



,\xio s . \xio s . 



y line. 

 \X10 8 . 



Zirconium 



Niobium 



Molybdenum... 

 Ruthenium ... 



Rhodium 



Palladium 



Silver 



Tin 



Antimony 



Lanthanum ... 



Cerium 



Praseodymium ...j 

 Neodymium ... 



Samarium 



Europium 



Gadolinium ... 



Holmium 



Erbium 



Tantalum 



Tungsten 



Osmium 



Iridium , 



Platinum 



Gold 



6-091 

 5-749 

 5-423 



4-861 



4-622 



4-385 



4-170 



3-619 



3-458 



2-676 



2-567 



(2-471) 



2-382 



2-208 



2-130 



2-057 



1-914 



1-790 



1-525 



1-486 



1-397 



1-354 



1-316 



1-287 



32-8 

 33-8 

 34-8 

 36-7 

 37-7 

 38-7 

 39-6 

 42-6 

 43-6 

 49-5 

 50-6 

 51-5 

 52-5 

 54-5 

 55'5 

 56-5 

 58-6 

 60-6 

 65-6 

 66-5 

 68-5 

 69-6 

 706 

 71-4 



40 

 41 

 42 

 44 

 45 

 46 

 47 

 50 

 51 

 57 

 58 

 59 

 60 

 62 

 63 

 64 

 66 

 68 

 73 

 74 

 76 

 77 

 78 

 79 



5-507 

 5-187 

 4-660 



4-168 



3-245 

 2-471 

 2-360 

 2-265 

 2-175 

 2-008 

 T925 

 1-853 

 1-711 

 1-591 

 1-330 



2-424 

 2-315 



3-928 



2-313 

 2-209 



1-972 



1-888 

 1-818 



1-893 

 1-814 



1-563 



1-201 

 1-155 

 1-121 

 1-092 



1-287 



1-172 



1-138 

 1-104 

 1-078 



not included in the limited range o£ wave-lengths which can 

 be photographed on one plate. Sometimes lines have not 

 been measured, either on account of faintness or o£ the 

 confusing proximity of lines due to impurities. 



Lines due to impurities were frequently present, but 

 caused little trouble except in the rare earth group. Here 

 two extreme cases occurred. The X-ray spectrum of the 

 praseodymia showed that it consisted roughly of 50 per cent. 

 La. 35 per cent. Ge, and 15 per cent. Pr. Unfortunately 

 the position expected for the a line of Pr coincides with the 

 known position of the /3 line of La, but the /3 line of Pr 

 was quite conspicuous, and had precisely the wave-length 

 anticipated. Two specimens of erbia were used. The speci- 

 men purchased contained 50 per cent. Er and 50 per cent, of 

 another element, of which the X-ray spectrum coincides 

 with the spectrum calculated for Ho. The erbia given by 

 Sir William Crookes was evidently nearly pure, but showed 

 the a. and f£ lines of Ho quite faintly, and also faint lines 

 agreeing with a. and /3 of Ds and a of Tm I and of Tm IT. 

 The Xd was free from La, Ce, and Pr, but contained a fair 



