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Anthropology. — “A new graphic system of craniology” by Dr. 
P. H. Eykman, at Scheveningen. (Communicated by Prof. 
C. WINKLER.) 
For a rough comparison of skulls, we often use three measure- 
ments, viz.: length, breadth and height. 
Because the review of these three is still too difficult, Scamipr, 
at Leipsic, proposed using the relative instead of the absolute meas- 
300 
AN: EES 
The sum of the relative becomes thus constant; that is: 300; and 
he then really only works with two instead of three respectively 
independent proportions, because the third is always equal to 300 
minus the other two relative measurements. If two are known, then 
the third is also definite and in an ordinary diagram, you could, 
by one point, find out the relative proportions of the skull. 
For practice this method is insufficient, because the third meas- 
urement, although it can be calculated, is not shown in the diagram 
and so escapes our notice. 
I have discovered a method, giving a graphic representation in a 
plane, showing three measurements that suffice, to denote that their 
sum is constant, and at the same time indicated by one point. 
We start from a trihedral angle (fig. 1), of which the ribs PQ, 
PR and PS represent a triple ordinate-system. 
ures, which he obtained by multiplying the last with 
By a single point d in space, we can in this manner show three 
absolute measurements at the same time. 
Suppose now we draw a plane, that crosses the three ribs at the 
same length, going through such a graphic point d, it would be 
easy to prove, that the sum of the three absolute measurements is 
equal to the length of one rib; viz.: 
Pe + Pg + Pb= PR= PQ = PS. 
If we suppose the rib to be 300, then this secant plane, that has 
the form of an equilateral triangle, will be the geometrical place of 
all graphic points, of which the sum of the three ordinates = 300; 
viz.: all points of the formula of ScumipT are in this triangle. 
Supposing there were planes parallel to the three sides of the tri- 
hedral angle, you could call them planes of measurement, and then 
these planes would show on the equilateral triangle, systems of 
