418 
Variation and Correlation of the Human Skull 
The determination of both (e) and (^) was for purposes of spurious correla- 
tion : see p. 461, below. 
(77) The face height to face breadth index (100 GHjGB). 
(0) The upper face height to face breadth index (100 O'HjOB). 
{k) The nasal breadth to nasal height index (100 NBjNH). 
(X) The oi'bital height to orbital breadth index for both right and left 
eyes (100 O^jO, .ii and 100 O2/O1 . L). 
(fx.) The palate breadth to palate length index (100 G2/G1). 
(v) The length to breadth index (100 L'/B) for greatest length. 
(tt) The length to height index (100 L'jH) for greatest length. 
{v) and (tt) again were only calculated as subsidiary calculations involved in 
other investigations. 
A knowledge of the profile length {GL), the skull basis {LB), and the upper 
face height (G'H) gave us the sides of the triangle formed by the mid-point on 
the frontal nasal suture, the nasion, the mid-point on the alveolar rim between the 
middle incisors, the alveolar point, and the mid-point of the anterior rim of the 
foramen viagnum, the basion. 
We placed these lengths on the trigonometer made for Professor Pearson by 
the Cambridge Instrument Company, and read off at once the three angles of this 
triangle*. But knowing the profile angle we were able to discover the angles 
between the skull base and the profile length and the horizontal plane. We have 
therefore besides the profile angle the following five angles : 
{cm) Profile angle (P), measured with Eanke's goniometer as described 
above : p. 414. 
(bh) Angle between upper face length and profile length, the alveolar angle 
{A Z ). Determined by length measurements and trigonometer as above described. 
(cc) Angle between skull basis and upper face length, the nasial angle 
(iVz). Determined as in (hb). 
* Professor Thane having much emphasised the importance of these angles, the trigonometer in 
question was devised for readily obtaining them with sufficient practical accuracy. 
