In the other method, as when the fingers are impressed on a carefully smoked surface of glass, the projecting ridges lift up the carbon of the soot, leaving a white pattern behind, with the sweat-pores forming black punctuations, while the receding furrows leave the black surface untouched. When such impressions have to be used again, as for evidence, they should be carefully varnished, as they are exceedingly liable to be destroyed by the slightest contact. In a case under judicial investigation where an official imprint had to be compared with one done by accident negatively on smoked glass or the like, the black lineations would not closely correspond--would, in fact, considerably diverge in pattern. This might tend to confuse judge and jury if the distinction of negative and positive dactylograph were not made clear by the expert witness. Then the apparent divergences could easily be demonstrated to be very significant coincidences. Five years of my early life were spent in learning a trade in Glasgow--that of the soon-to-be-obsolete Paisley shawl manufacture. It seemed to me to have been an utter waste of time, but part of my duty was to deal with the arrangement, classifying, and numbering immense varieties of patterns, printed with every conceivable variation of combined colours. It was impossible to carry these on memory, and one had to resort to mnemonic means of classification. Now, the immense significance of the variety in human finger-patterns dawned upon me very early, when I had once begun to interest myself in them. [Illustration: DESIGN-LIKE PATTERNS IN FINGER-PRINTS NO. 1. (Diagrammatic)] [Illustration: DESIGN-LIKE PATTERNS NO. 2.]