E. M. Eldbrton 
295 
Now (j)i(ij) luid (f)-,(ij) for given t/'s are the values debermiiied in Table I for 
the constants at each age of the regression lines 
W=-A+BH, 
and n is the number of children dealt with at each age. Our type equations are 
then of the form : 
a, + ia,^(ny) + ^a,^ (nf) = (A), 
ia„S (ny) + l,a,% (iif) + (ny^) = (Aij), 
iaoS (nf) + iaiS (nf) + ia,2 (ny^) = iS (Af), 
and similar equations for ?>„, bi, h.^, with 5 for A. 
When these constants had been determined we put Y= \0 + y and obtain the 
equations given in Table II. 
TABLE II. 
GldSf/oxK ScJwol Childi'en. 
TF= Weight in lbs. H='iie\g\\t in inches. J^=True age. 
Boys 
Group A {-02181 r2 + 2-214 --2554 Fl xH- {1-I3275r2+ 67-542- 14-74171'), 
„ B Tr= {-01533 ]'2 + l-900--1493F! x 77- { -833147-+ 53-101- 9-8662F}, 
„ C IF= {-03990 FH 3-614- 5796 F} X 77- {2-08397 FH 139-456 - 31-6570 F} , 
„ D Tr= {-02983F-'4-2-799--.3636F} x77- !l-76624FHlll-407-24-0174F}. 
Girls 
Group ^1 Tr= {-01880FH1'657--1644F} x7^- { -96454F- + 38-119 - 9-7305 J'J , 
„ B W= {-02081 F2 + 1-907- -2043 F} x H- {1-16330 F2 + 60-230-13-6925F}, 
„ C ir={-02315F2 + 2-222--2457F} x77- {1-21642F2 + 67-626-14-3416J';, 
„ D ir= {-02701 F-' + 2-.385 --2832 F} x 77- {1-.56165 F2 + 87-624 - 18-9239 F) . 
A model of the surface for Glasgow Girls of Class B has been made by 
Mr Soper. Allowing for the points based on few observations at the end of each 
regression line of weight on height for constant age, the scroll represented by black 
threads is quite a good fit to the observations represented by card sections. The 
model is, however, difficult to photograph in a manner which shows effectively the 
approximation of the thread scroll to the cut card sections. The reader should 
note that an additional thread is placed between each of the threads which 
graduate the regression lines for the different ages. 
Further eight tables (Tables a — 6) have been constructed in order that the 
average weight of any boy or girl of a given height and age can be read off at once. 
See pp. 300 — 303. It has been stated before that the age groups in Glasgow are 
from .5-5 to 6-5 years etc.- and that G, 7, 8 etc. are the centres of each age group, 
38—2 
