PROCEEDINGS 
OF THE 
ROYAL SOCIETY OE EDINBURGH. 
VOL. XXXI. 1910-11. 
I. — Craniological Observations on the Lengths, Breadths, and 
Heights of a Hundred Australian Aboriginal Crania. By 
A. W. D. Robertson, M.D. Melb., Government Research Scholar 
in the Anatomy Department of the University of Melbourne. 
Communicated by Professor R. J. A. Berry. 
(MS. received March 30, 1910. Read May 16, 1910.) 
The present work forms the first portion of an investigation into the 
craniological characters of the Australian aboriginal crania at present 
being conducted by the author, and is part of a general scheme for the 
osteological investigation of the Australian aboriginal initiated by the 
Professor of Anatomy in the University of Melbourne. 
There are, as is well known, two methods of treating craniometric 
statistics, and which, for convenience, may be designated (1) The Empirical 
Method ; (2) The Rational Method. 
The object aimed at in both is to find numbers that shall be character- 
istic of the race of any country. 
“ The Empirical method places very little value on the length and breadth 
of a skull except as a means of arriving at their ratio — the cephalic index — 
‘ the subdivisions of which,’ says Gray (15), ‘ are all arbitrary.’ Some, e.g. 
Retzius, made use of centres ; others, e.g. Welcker, made use of limits, and 
there appears to be no special reason for fixing the limits of the groups at 
one index more than another. The analysis of craniometrical statistics by 
this method becomes comparatively simple: calculate the cephalic index 
and other indices for each individual, and find the average or mean index 
for the whole group of people measured. The highest and lowest index is 
usually stated as indicating the range of variation on each side of the 
VOL. XXXI. 1 
