"Now," Daniel said. "Even I know that coiners frequently make their counterfeits by joining two faces stamped from gold foil, and filling the void between them with solder. The solder is both lighter and softer than gold. This provides two means of detection: one may weigh the coin, or bite it. Either should suffice. In particular, if a coin has passed the test of weighing, its value should be confirmed beyond doubt! For nothing is heavier than gold. Any adulteration should be betrayed by a want of gravity. The weighing test ought to be infallible. And yet this chap—who really is extremely knowledgeable concerning coins—felt it necessary to make the additional test of biting. Is there any reason for it? Or was he being foolish?"