CHAPTER V

PATTERNS: THEIR OUTLINES AND CORES 64

My earlier failures in classifying prints; their causes 64-66

The triangular plots 67

Outlines of patterns--eight sets of ten digits given as examples 69-70

Supplies of ridges to pattern 71

Letters that read alike when reversed 71

Magnifying glasses, spectacles, etc. 72

Rolled impressions, their importance 73

Standard patterns, cores, and their nomenclature 74-77

Direction of twist, nomenclature 78

Arches, loops, whorls 78

Transitional cases 79

The nine genera 80

Measurements--by ridge-intervals; by aid of bearings like compass 82-84

Purkenje--his _Commentatio_ and a translation of it in part 84-88