NOVEMBER 20, 1913] 
(1) The observations were obtained by a 5-in. theo- 
dolite reading to 30” of are. 
‘(2) That the results given from angles of depression 
from Jebel Serbal to points nearly 180° apart show 
(a) that the theodolite was in perfect adjustment, and 
that the height obtained from a distance of fifty-eight 
miles on the north side differed only 116 ft. from the 
height obtained at a distance of 24-9 miles on the 
south side. 
(3) Although observations obtained with imperfect 
instruments—and what instrument is perfect ?—may 
give results not perfectly accurate, I cannot admit that 
the corrections applied should not be as accurate as 
they can be. 
(4) Dr. Ball is correct in stating that a distance of 
fifty-eight miles an error of one minute in the angle 
of depression means a difference of about roo ft. in 
the result. 
tion in altitude of the horizon in the Arctic should be 
18 minutes and not 18 degrees. This is a printer’s 
error. T. H. Tizarp. 
The Piltdown Skull and Brain Cast. 
TueE~excellent figure of the Piltdown brain cast 
which accompanied Prof. Elliot Smith’s last letter 
(Nature, November 13, p. 318) brings out clearly 
the differences which separate him and me. His 
figure represents a brain with approximately sym- 
metrical right and left hemispheres, so far as these 
are viewed from the hinder or occipital aspect. If, 
then, the anatomical parts occupy corresponding posi- 
_ tions on the two sides, he has solved the problem of 
a considerably smaller brain than I had postulated. 
I have made a tracing of his reconstruction in order 
to fill in with some details the exact relationship 
of parts represented by his drawing. It will be seen 
he has obtained symmetry by the most simple means. 
In the original brain cast the right hemisphere of the 
brain measured only 555 cubic centimetres, the left 
half 645 c.c.; this difference of 90 c.c. referred only 
to the hinder part of each hemisphere. In Prof. 
Elliot Smith’s reconstruction the hemispheres have 
been balanced by moving 
or beyond the middle line and enlarging the left 
_ hemisphere. The middle line which Prof. Elliot 
Smith has selected is exactly that used by Dr. Smith 
_ Woodward in the reconstruction of the skull, not that 
which he employed when building up the brain cast; 
in building up the brain he employed another middle- 
line altogether. 
In the accompanying tracing of Prof. Elliot Smith’s 
reconstruction I have indicated the longitudinal blood 
sinus which sweeps widely (10 mm.) to the right as 
it passes between the occipital poles of the brain. 
The left pole exceeds the right to'a degree which is 
seldom seen in even the highest forms of modern 
human brains. Seven years ago Prof. Elliot Smith 
published a short paper (Anat. Anz., 1907, vol. xxx., 
P: 574), which is justly regarded as authoritative. He 
directed attention to the preponderance of the left 
_ occipital pole of the brain, 
_ Ponderance to the specialisation of the right hand; 
Bett he retains the present reconstruction, have to modifv 
_ to some extent the opinion he has expressed of the 
brain of Piltdown man—that it is “the most primi- 
: tive and simian brain yet recorded.” As regards the 
NO. 2299, VOL. 92] 
(5) He is also correct in his surmise that the varia-_ 
how to reconstruct the Piltdown skull so as to obtain | 
the left hemisphere towards 
NATURE 345 
asymmetry of the occipital poles, it is, in my opinion, 
_ ultra-modern. 
_ Prof. Elliot Smith has frankly stated that his recon-- 
struction is not, in the strict sense of the word, a 
cranial cast—a cast taken from the interior of a 
reconstructed skull; it is a reconstruction built up—as 
the original brain cast must have been—from impres- 
| sions taken from the inner or cerebral aspect of the 
cranial bones. To test such a brain reconstruction 
$0 
SO 
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Fic. 1.—Tracing of Prof. Elliot Smith's reconstruction of the brain-cast 
with certa in additions. (Half nat. size.) 
the actual fragments of the skull must be placed over 
the corresponding parts of the brain cast. When that 
is done it is at once seer that in securing a symmetry 
of the brain hemispheres the corresponding parts of 
the skull are thrown somewhat out of position. On 
the tracing of the reconstruction (Fig. 1) I have 
| drawn a line, x—y, across corresponding angles of the 
parietal bones. That of the right side is a centiinetre 
| higher than on the left; on the right side the lamb- 
& 
Poster Lord th 
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| 
Fic. 2.—Tracing of the right fragment of the parietal (Piltdown) fragment 
(broken line) superimposed on the right ps (continuous line), (Half nat. 
size, 
doid suture passes outside the 50 mm. vertical line; 
on the left it stops short of that line. 
It may be questioned if the hinder, lower angle of 
the parietal bones do correspond. That was the 
| very first point I set out to determine when I 
found there was such a discrepancy between. the 
size of the Piltdown cranial fragments and the 
brain capacity which Dr. Smith Woodward had 
ascribed to this earliest known form of man. That 
is the first step which has to be taken. In Fig. 2 
