W. K. Macdonell 
203 
(5) On the Detennination of the Capacity. 
In determining the capacity of the skulls, I used very hard, dry mustard seed, 
and my procedure was as follows. Through a tin funnel placed in the foramen 
magnum, I poured in a quantity of seed enough to fill the cavity about half-full, 
and then gave it a vigorous shaking, so as to get the seed well into the frontal 
part of the skull; I then filled up the cavity with more seed, to the rim of the 
foramen magnum, and shook and tapped ; the seed of course flowed away in all 
directions, and I proceeded to fill up, and shake and tap again. This process went 
on until I was satisfied that I could get practically no more seed into the skull, 
but one of the greatest difficulties in the operation was to decide when this point 
was reached : often, when the skull seemed quite full, a turn of the hand would 
cause the seed to slip away into some unsuspected empty nook, leaving a vacant 
space round the foramen magnum. Indeed, in some of the skulls, I doubt if I ever 
succeeded in quite filling the cerebellar fossae. 
The filling process being finished, the seed was poured from the skull into 
a tin can, and from thence through a funnel into the measuring glasses. I had to 
use more than one of these, as the largest had a capacity of only 1000 cm.l The 
process of shaking and tapping then went on with the glasses as with the skulls, 
until the subsidence of the seed appeared to come to an end, and the volume was 
then read off on the scale. 
In this way I dealt with the first 31 skulls of the series which were sv;ffi- 
ciently well preserved to admit of their capacity being determined, but obviously 
the process was tedious, as two measuring glasses had to be shaken and tapped 
for each skull, and it seemed doubtful whether I could obtain a fairly uniform 
density of seed in the glass measures in a series of operations extending over 
several weeks. Another doubt also suggested itself — was the density of seed in 
the skull the same as the density in the glasses ? 
It then occurred to me to weigh, instead of measuring, the seed contents of 
each skull, and then reduce the weights to volumes, having ascertained once for 
all the weight of a known volume of the seed. Accordingly I procured a good 
balance, capable of weighing up to 1500 grammes, and a copper vessel, with 
a counterpoise, for holding the seed. The skulls having been filled in the way 
described above, the contents were emptied into the copper vessel, which was then 
placed on the scale-pan, and the weight determined. 
The relation between weight and volume had next to be found. The 
obvious course was to find a skull of known capacity, fill it with seed in the 
same manner as the Whitechapel skulls had been tilled, and then weigh the 
contents. Professor Thane kindly placed at my disposal three "cranes etalons " 
which had been specially prepared, some years before, for having their capacity 
measured. They had been sawn horizontally into two pieces, and the inner 
surface painted with a thin coating of waterproof varnish ; the two pieces had 
then been cemented together again, and the whole made watertight. I filled 
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