320. Direct writing is still easier to imitate ; with out speaking of well-known chemical agents for mak ing writing appear in a given time on a blank piece of paper, which may be exposed by the most ordinary precautions, it might happen that, by skillful trickery, one piece of paper could be substituted for another. It might be that he who might wish to deceive would have the art of distracting the attention while writing a few words. We have been told that writing has been produced with a small crumb of lead hidden under the nail.
