January 28, 1904] 
NATURE 
295 
line, as follows:—Some marked peculiarity is determined 
on to be made the subject of study. It may be an excess or 
deficiency of some normal character, or it may be a trait, 
a feature, a disease, or a monstrosity, the process being 
the same in all these cases. The inquirer then endeavours 
to trace its hereditary distribution. He fixes upon some 
individual who possesses the peculiarity in a highly marked 
degree, and traces the frequency and intensity with which 
it occurs among his kinsmen. He tries to do so ex- 
haustively by compiling the facts relative to those kinsmen 
in each and every degree to as great a distance of kinship 
as he is able, or cares, to go. He follows a similar course 
in respect to many other individuals belonging to as many 
different families, and finally he obtains average results by 
well-known methods. I am speaking solely of inquiries 
Distribution of the Peculiarity X in the Family of A. B. 
/a=Father or father's, according to its place ; similarly, »e=Mother ; 
éro=Brother ; si=Sister ; so (or son where more euphonious)=Son. 
The links in the chain of kinship are to be read as leading outwards 
from A.B. Thus, me da signifies ‘‘A.B.’s mother’s daughter is.” 
fa bro son means “‘ A.B.’s father’s brother's son is.” 
| | | 
| Adults alone Adults alone | 
ae | _|| : SSS || Names)in 
Ordinary | h WES ov || Titles ww 4 2 2 full of those 
names'foe irs owing I's 3 3 5 || showing | #6 8 whose ini- 
generalised | us 3 ail ea Pree | 6u| = 3 tials appear 
kinships chain of Zul seh | chain of [7-5] 5 » = in the 
kinships = Flas | kinships < =) 28 o preceding 
S2| S36 | Se S35 column 
| =o/-2 ¢ Fiojes oo 
| a eS os || | ee = uw 
Grandfather | fa fa 5 | || me fa | x | 
Grandmother | fe me I | me me a || | 
= | 
Uncles... ...| fadro | | me bro | 
Aunts ... ...| fast || we sz 
Father... ...| father mM | — _— — 
Mother... ...| wzother | 1 | — = _ 
- | {|—_———_| — |__| 
Brothers ...| drother | | — \— _ 
Sisters ... ...| stste7 | — —}; = 
= | | | 
Half-brothers| /a son \| me son | ; | 
Half-sisters | fa da \| me da 
a \| 
Nephews _ ...| dro son | si son 
Nieces... ...| dra da | st da | 
2 = = | 
First cousins | fa 470 son) | || ee br0 son 
Male ...| fa sf son | || te sZ son | 
— — _—— — 
First cousins | fa bro da | me bro da 
Female...) fa sz? da | | me si da 
| 
—— ——————————— — ————— | 
Number who) Initials 
: - r survived of those 
Maidenmameof the wife | Yearof| ° fs 
marriage) infancy | whose X | 
} deserves | 
sons | daus | record 
| 
directed to what I would call the actuarial side of heredity 
because they are analogous to those made by actuaries with 
medical experiences to determine the just rates of insurance 
in respect to expectation of life and other vital phenomena. 
The ambiguity and cumbrousness of the ordinary terms 
of kinship are serious obstacles in carrying out these re- 
searches ; it is also very difficult to present the results in a 
compact form by any established method. I have en- 
deavoured to overcome both difficulties, the latter by the 
arrangement of the present table, and the former by the 
use of syllables, which give a perfectly distinctive descrip- 
tion, and which, in addition to the advantage of brevity, have 
those of being easily intelligible, euphonious, even though 
they may be a trifle absurd, and capable of the most ex- 
tended application. The details of the peculiarity X, as 
they appear in the several persons named in the last’ column 
NO. 1787, VOL. 69] 
of the table, are supposed to be entered in a corresponding 
number of paragraphs on a separate sheet. After more 
trials and failures than would be easily credited, I think I 
have at last succeeded fairly well. Still, as I began by 
saying, I should be very grateful for useful suggestions. 
The table admits of indefinite extension, with no alteration 
of method. It will, of course, be understood that each 
successive step in the line of descent introduces a new 
element that may seriously affect the previous influences. 
Much might be added, but I think that with the aid of a 
little reflection the arrangement of the table will explain 
and justify itself. Francis GALTON. 
The Source of the Energy of Radium Compounds. 
Ir I understand Prof. Rutherford’s communication aright 
(Nature, January 7, Pp- 222), he concludes from the con- 
stancy of radio-active results with a solid radium salt and 
the same diluted that the energy of radium compounds 
cannot be derived from external sources. The matter is of 
such wide scientific interest that I ask your permission to 
present concisely the contra argument. 
(1) When a coloured solid is dissolved the amount of 
absorption of light effected by the solid is equal to the 
amount of light absorbed by its solution. Thus I have 
shown that a plate of solid bichromate of potash o-71 milli- 
metre in thickness effects the same absorption of light as 
6 centimetres of solution containing 0-0309 gram of the 
salt per cubic centimetre, as in each case the same number 
of bichromate molecules or molecular aggregates is act- 
ing on the light. To be perfectly clear, taking the specific 
gravity of bichromate of potash as 2-617, we have in the 
former case a rectangular bundle of rays 1 square centi- 
metre in section passing through 0-71 x0 26170-1858 gram 
of solid, while the bundle of rays in the latter case passes 
through 6X0-0309=0-1854 gram of dissolved bichromate 
(see Chem. News, October 5, 1877). 
(2) It has been amply demonstrated that the absorption 
of X-rays follows the same general laws as the absorption 
of light; thus the amount of both kinds of radiation 
absorbed increases (1) with the thickness of the body passed 
through, and (2) with the molecular weight in a comparable 
series of bodies (‘‘ The Old Light and the New,’ 1896, 
pp- 73-80). 
Therefore if it be postulated that the energy of radium 
is due to the absorption of ‘‘ an unknown external radi- 
ation?’ ‘* similar in character to the radiations which are 
emitted,’? viz. the y rays, then the mere act of dilution of 
a milligram of radium bromide will not affect its constancy 
of absorption, and therefore also will not materially 
influence its radio-activity. Witiiam ACKROYD. 
Borough Laboratory, Halifax, Yorks. 
y-Rays from Radium. 
From the letter of Prof. Rutherford in Nature of January 
7 it is improbable that y rays from radium are Rontgen 
by self-bombardment. The y rays must 
rays generated 
therefore arise from radium directly, and not as a secondary 
effect of bombardment. a 
It may be useful here to recall a remark made by Sir 
George Stokes at a meeting of the physical colloquium of 
the Owens College, Manchester, shortly before his death. 
Commenting on Becquerel rays, he likened the discharge of 
kathode rays to the discharge of a gun, the impact of 
kathode projectiles on a target creating an ethereal dis- 
turbance recognised as Réntgen rays. But, he said, in the 
same way as there is an explosive disturbance in the gun 
where the bullets issue, so there must also be a violent 
ethereal disturbance, not only where kathode rays strike, 
but also where they issue. 
Is it not just this disturbance where 
is now being detected in y rays, and is 
sistent with this view that the explosive 
atom which produces a and f rays should at 
time generate something akin to Roéntgen rays: 
J. R. Asnwortu. 
105 Freehold Street, Rochdale, January 10. 
B rays issue which 
it not quite con- 
disturbance of the 
the same 
