L. ISSERLIS 
61 
The authors give the value of a generalized H, obtained by direct calculation 
in two or three cases. The material they deal with is the distribution of births, 
deaths and populations in 1000 English registration sub-districts, and also of the 
birth- and death-rates and populations in these districts. The material is highly 
heterogeneous and exceedingly high values of occur. Thus, /3i for deaths is 
16-0205 and for death rates is 61-5392. 
Unfortunately in their table on page 341 of the values of the simple t^'s, the 
authors fail to discriminate between yiq^ and ^rjy. 
Mr Greenwood, at my request, was good enough to consult his MS. notes and 
sent me an identification table of the tj's, but a recalculation of the -q of populations 
on births and the r] of populations on deaths has shown that errors have crept 
into this identification table. 
When amended this table is as follows : 
,77, = -9501, 
„7j^ = -9358, 
= -9241, 
,7?, = -7855, 
.ly = -7527, 
y-n, = -8871, 
where x = population, y = births, z = deaths. 
With these values our equation (70) gives 
xyH^z ^yR"r, = -2691, 
or ^yH\ = -8814, 
and ^yH, = -9388. 
The authors give as the empirical value ^yH^ = -9384. 
As regards the use of the simpler formulae, the only of reasonably small 
value is jS^ of population which equals -0886. 
1 -I- r2 
We TJut — = '^'^ I — r2 1 
^' xy 
or ^yR\ - (-7825)2 = [(-9241)^ - (-7822)^], 
or ^yH\ = -87200, 
xyfl^ = -9338. 
Considering the wide divergence in the results obtained by the authors when 
dealing with the 1000 sub-districts and with 999 of them* it is evident that the 
use of the above simple formula would have been sufficient for their purpose. 
* I.e., p. 343: ,,opui.iio„ ami birti,., -ffdcati,, =-9384 for 1000 sub-districts, and =-9213 for 999 sub-districts. 
