u 
Dr. D. F. Comstock on the 
however, the International Atomic Weight values for 1907 
instead of those Rydberg used. 
He .. 
Li .. 
| Be .. 
i'B 

2 - 
o 
Fl .. 
Ne .. 
Na .. 
Mg.. 
Al .. 
Si .. 
M. 
I 3 
! 4 
5 
: ? 
I 8 
: 9 
10 
11 
12 
13 
14 
2M. 
2M4-1 
4 
i 
8 
11 
12 
15 
16 
19 
20 
23 
24 
27 
28 
Atomic; 
Weight. D. 
Sign. M. 
4 
703 
91 
11-0 
12-00 
1401 
16-00 
190 
200 
2305 
24-36 
27-1 
28-4 
— P... 
•03 S... 
1-1 CI 
•0 A .. 
K 
—99 Ca 
'0 Sc 

•o 
•05 Ti 
•36 V 
•1 Cr 
•4 Mn 
Fe 
15 
16 
17 
18 
19 
20 
21 
22 
23 
24 
25 
26 
27 
28 
N. 
2M.2M+1 
32 
36 
40 
44 
48 
52 
56 
31 
35 
39 
43 
47 
51 
55 
I 
: Atomic 
Weight. 
D. 
310 
•0 
32-06 
•06 
3545 
•45 
399 
3-9 
39-15 
•15 
40-1 
1 
44-1 
1-1 
48-1 
1 
51-2 
2 
52-1 
i 
55-0 
•o 
559 
1 
The orderly arrangement of the series is striking. It will 
be noticed that in three cases only are the D's greater than 
unity and only in two cases are they negative. 
Rydberg points out that although the heavier elements do 
not conform well to this scheme, L e., do not in general give 
the small fractional values of (D) noticed above, yet this is 
in reality no valid objection, for the numerical values of the 
weights of heavier elements depend much more on the value 
of the arbitrary unit chosen than do those of the lighter 
weight elements, and hence they can have little influence 
one way or the other in estimating the validity of the curious 
relations he sets forth. 
The whole question is of course whether these differences 
represent real physical deviations from something or whether 
they are merely mathematical remainders. Rydberg certainlv 
believes them to represent physical realities, and considering 
the before-mentioned overwhelming improbability that the 
approximation of the atomic weights to whole numbers is due 
to chance, we can hardly doubt that he is right. 
13. Now it is to be noticed tbat these deviations find a ready 
explanation when the conclusions of the present paper are 
combined with the theory, so much favoured recently, that 
one element breaks down into two or more others with an 
accompanying expulsion of energy. The deviations are then 
to be explained as resulting from Joss of mass accompanying 
the dissipation of energy. On the other hand, if no such loss 
of mass takes place, the existence of these deviations in the 
