My readers may accept it that the ink used was the same Indian ink with which the Chinese characters on the note were written. That is the unhesitating judgement of such an expert as Mr. Galton, who examined it. The difference between a water ink and printer's ink for identification is enormous. Blood on the fingers has occasionally left impressions that fortunately sufficed to reveal the murderer; but, as a rule, wet fingers leave only smudges as useless as this one. It is quite certain, therefore, that no one in the habit of impressing his thumb-mark as this banker did, would use water ink, if he depended on recognizing it as his own. In short, the smudge on the bank-note was placed there in order to identify the two parts of a piece of paper after severance, not to prove who placed it so. My readers may see what exquisite delicacy of detail can be obtained by printer's ink, when so desired, if they will examine a fine skin impression with a magnifying-glass; even the pores along the ridges can be seen as white dots. For practical purposes, however, such extreme delicacy as this is not needed. This difference of ink suggests a further remark. The Chinese have used printer's ink for ages. If they aimed at identification they would surely have discovered its great value for clear impressions, and its use could never have died out. On the other hand, a method of identification depending on water ink could never have survived for such strict work as our finger-prints. On the palm of the hand it can give a fairly good impression for such simple identification as is wanted (say) for passports, because the large creases will obviously be those of the bearer of the passport, or as obviously not. These lines of the palm, so well known in palmistry, are as clear to a man as the shape of his hand, while those on the pads of his own fingers are scarcely noticed even now by one man in a million. The science of identification by means of the pads cannot, in my opinion, date farther back than 1858, when I happened to use oil-ink, which was not used for _tep-sais_.