The London, Edinburgh and Dublin philosophical magazine and journal of science . or as g^Qu = 0*()78 and pCu<7 is supposed to be negligible, P M £=-,£. 0;00678 (18) In the following table we again find the mass scatteringcoefficients for the elements 1-20, calculated by theformula (18). Table scattering coefficients for the elements 1-20. Atomic Number of -, calculated according to number. Element. outer electrons. P Z. formula (18). formula (19) 1 H 1 0-432 0-205 3 Li 3 0-187 0205 4 Be 4 0-190 0-205 5 B 5 0-196 0-205 6 C 4 0-144 0-137 7 N 7 0216 0-205 8 0 4 0-108 0-103 9 F 5 0
The London, Edinburgh and Dublin philosophical magazine and journal of science . or as g^Qu = 0*()78 and pCu<7 is supposed to be negligible, P M £=-,£. 0;00678 (18) In the following table we again find the mass scatteringcoefficients for the elements 1-20, calculated by theformula (18). Table scattering coefficients for the elements 1-20. Atomic Number of -, calculated according to number. Element. outer electrons. P Z. formula (18). formula (19) 1 H 1 0-432 0-205 3 Li 3 0-187 0205 4 Be 4 0-190 0-205 5 B 5 0-196 0-205 6 C 4 0-144 0-137 7 N 7 0216 0-205 8 0 4 0-108 0-103 9 F 5 0-114 0-114 11 Na 7 0-132 0-130 12 Mg 4 0-071 0-068 13 Al 5 0-080 0-079 14 Si 4 0-061 0-059 15 P 7 0-097 0-096 16 S 4 0052 0-051 17 CI 5 0-061 0-060 19 K 7 0-077 0-076 20 Ca 4 0 043 0041 202 Dr. Tycho E:son Auren on In fig. 4 the connexion between ^, calculated by the Pformula (18), and Z is given graphically. As we findfrom the figure, the values, except for H and Li, aredistributed to three hyperbolas corresponding to p=77p = 5,p = 4: respectively. 0-4- 0-3 0-2 0-1 Fiy. 14- 16 But in regard to H, the Table XIY. shows that the massscattering coefficient also may be expressed by the formula £ _ 0-205p P- z ? (19) For elements, in case of which p = Z, that is identical withthe known value given by Barkla for the light case of H, the formula (19) is not applicable and bymeans of it we get a value that is merely about half thereal. This, however, is in good agreement with experience ;for after what is shown by the experiments of Barkla and Crowther, - is twice as great for H as for other lighter elements. The exceptional position seemingly occupiedby H is in appearance only, and may be fully explained ifone takes as granted that not all electrons which constitutethe atom, but merely the outer ones, give off scattered the other hand, as has been clearly made out, not onlyby above-mentioned experiments on C, N, and O, but also the Absorption of X-Rays. 203
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