called carbonic: it possess the advantages of extreme blackness and durability, the writing remaining fresh so long as the substance on which it is written exists; but as it does not sink into the paper, it is liable to the great inconvenience of being easily and entirely removed; for, if a wet sponge be applied to it, the writing may be washed away, and no traces of the characters will remain. The facility with which documents might be thus obliterated, gave occasion to fraud, as an artful forger was able to remove such portions of the original writing as he might desire to get rid of, and thus profit by the absence of material words, or insert in the blanks which he had made, such interpolations as might serve his turn. Many common accidents, by which books and writings were exposed to wet, or even to damp, were also fatal, or at least highly injurious, to compositions and muniments of great value. Various expedients were therefore attempted to remedy an imperfection from which many must have suffered severely. Pliny informs us that it was usual, in his time, to mix vinegar with the ink, to make it strike into the paper or parchment, and that it, in some degree, answered the purpose. It should seem that vitriolic ink, such as we use at present, was also adopted soon afterwards,
