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Photographic Researches and Portraiture   321

At the British Association in 1898 Galton applied for and obtained the appointment of a committee consisting of Professor E. B. Poulton, Professor W. F. R. Weldon and himself "to promote the systematic collection of Photographic and other Records of Pedigree Stock." This Committee made a Report to the Association meeting at Dover in 1899 and it was published in the B. A. Report for that year (pp. 424 X29). The report emphasises the fact that while it is possible in the various Stud-books and Herd-books to trace the ancestry of pedigree stock, these works

"afford scant means for obtaining that distinct presentment of each of the nearer ancestry which is needed for an exact study of the Art of Breeding." (p. 424.)

Information is almost entirely confined to colour, or in of horses to height at the withers. While photographs exist it is very difficult indeed to obtain those of sire, dam and produce as adult. what Galton terms a genealogical triad-and groups including the grandparents, even in the case of pure-bred shorthorn cattle, are practically unattainable'. The reason Galton finds is not far to seek

"Heredity is a comparatively new science and few people are as yet acquainted with the character of the records most suitable for its study, or are sufficiently impressed with the need for their exactness and persistence. The most important of these records which it seems feasible

to obtain are photographs, not merely pretty and well worked-up productions satisfactory to an artistic eye, but rather such as are analogous to the portraits made of criminals, for storage at the central police office, to serve as future means of identification. The desired photographs need to be taken under such conditions as shall ensure their being comparable under equal terms and shall admit of the accurate translation of measurements made upon them into

corresponding measurements made on the animals themselves." (p. 424.)

The report then describes the Standard Conditions. These are modified considerably from those given in the Nature paper. There is to be a solid wall or screen painted blue, a solid pathway in front of it of 6 feet width of lightcoloured bricks to show the horse's hoofs up in the photograph. Two lines are drawn on the pathway, one two feet from the wall, and the other two feet from the first; the edge of the path towards the camera is to show in the photograph as a sharp line. On the wall are to be small marks or studs each about the size of a sixpence, arranged in three vertical and three horizontal lines each at an exact distance of 3 feet apart, the bottom row being at a foot above the path level; the camera is to be 30 feet from the wall, and its optical centre at a height of 5 feet.

"The equivalent focus of the lens should not be less than 9 inches, otherwise the photograph will be too small for convenient measurement; the lens used in the experiment [at the Royal Agricultural Hall in March 1899] was of 13 inches focus, with plates of 61 x 43 inches, and

proved exactly suitable." (p. 426.)

The verticality of the focal plane and its parallelism to the wall are ascertained by the squareness of the stud-network of the wall on the focal plane screen. The camera once adjusted is to remain undisturbed during a whole series of operations. Prominent points on the horse or on cattle may be marked by

' What Galton wrote in 1899 remains equally true a quarter of a century later.
PGII   41