Photographic Researches and Portraiture   325

To conclude our consideration of this matter we must give some account of the published papers of 1906 and 1907, and of Galton's unpublished ideas as to "blurrers."

I deal first with the paper of 19071. Galton writes:

"It will be shown that it is easy to 'lexiconise' portraits by arranging the measurements between a few pairs of these points [standardised or"cardinal points] in numerical order, on the same principle that words are lexiconised in dictionaries in alphabetical order, and to define facial peculiarities with greater exactness than might have been expected." (p. 617.)

The cardinal points selected by Galton are (c) the tip of the chin (pogonion), (n) the tip of the nose, (f) the hollow between nose and brow (nasion), (m) the hollow between upper lip and nose, (1) tip of lower and (u) tip of upper lip. None of these are really points but vaguely limited regions, and Galton proceeds to define them more closely. A tangent to chin and nasal hollow YY is drawn, a line Y' Y' parallel to this to touch the nose is then drawn, and finally a tangent to nose and chin intersects YY and Y'Y' in points C and N, which give the first two cardinal points. A line drawn from N tangential to the nasal hollow gives F by intersection with YY, and tangents

Diagram viii.

to the region m from N and C intersect in the cardinal point M. To obtain the upper lip point U we draw a tangent parallel to CF to touch u and a tangent to touch u from N, their intersection is U. Similarly we draw a tangent to l parallel to CF and to l through C and their point of intersection is L. Galton found that the position of the six cardinal points F, C, N, M, U, L, when reduced to a common scale in which CF represented 100 units or "cents'," was sufficient to "lexiconise" profiles. The processes might

1 "Classification of Portraits," Nature, Vol. Lxxvi, pp. 617-18, October 17, 1907.

2 A "cent" on the mean profile for a life-sized adult portrait is about 1.25 mm. or I inch.