PALM AND SOLE IMPRESSIONS. 393 



The records employed are the printed impressions of the ten digits 

 placed in a definite order upon a card, and the separate cards are placed 

 on file by means of a classification wholly dependent upon the indi- 

 vidual patterns. 



Of those latter there are three types, the arch, the loop and the 

 whorl, designated in descriptive formulae by their initial letters. A, L 

 and W (hence the name of 'the alw system' by which Galton has 

 designated it). Of these the loop, which may turn to either the radial 

 or the ulnar side of the hand, is for some purposes farther subdivided 

 into radial and ulnar loops designated respectively as E and TJ. The 

 patterns are definite in their nature; transitions between them are of 

 rare occurrence and these are nearly always referable to one type or 

 the other. This system of 'ALW,' with the occasional subdivisions 

 of the E and TJ, forms what Galton designates the 'Primary Classifi- 

 cation/ and the finger tip records of any number of individuals are 

 arranged in accordance with a preconceived order. Although he has 

 made several experiments in this, in his final method (1895) the sets 

 are first arranged in four divisions (AEUW) in accordance with the 

 type of pattern found upon the right index finger. This is followed 

 by (small) letters designating the patterns upon the middle and ring 

 fingers of the same hand, using 1 instead of r and u for all looped 

 patterns. This will be seen to subdivide each of the first four divisions 

 into 9 or will divide an entire set into 36, as follows: 



If, now, the prints in each of these 36 divisions be farther subdi- 

 vided in accordance with the same three fingers of the left hand, each 

 subdivision consisting likewise of 36 compartments, the entire collec- 

 tion will be divided into 36^ or 1,296. The thumb and little finger 

 of the right hand which show 9 possible combinations, will subdivide 

 each of the 1,296 compartments and, in like manner, the patterns of 

 the thumb and little finger of the left hand will give another sub- 

 division of 9, so that the number of possible compartments or sub- 

 divisions into which a set of prints may be arranged by means of this 

 primary classification alone is 1,296 X 9 X 9 or 104,976; and since 

 the various combinations with a few exceptions occur with about the 

 same frequency, the number of separate prints in a collection of five 



