to preserve to us—if we be not wanting to ourselves in diligence—many precious relics of ancient lore. The restoration of the original writing in a palimpsest manuscript will be best explained by referring to one of the many kinds of sympathetic ink, which is in truth, making common ink ex post facto, or uniting the ingredients of which it is composed, after the fact of writing. If we write with water in which copperas has been dissolved, the letters will be invisible; but when the paper has been washed over with an infusion of galls, they will appear gradually, and will in time become tolerably legible; the ink being thus formed upon the paper, although much less perfectly, than in the ordinary maceration."
Little or nothing can be added to the full and elaborate history of ancient and modern inks which is contained in this extract,—so thorough and complete in its analysis of the subject, and so clear in its distinct statements of the results of investigations in which some of the most acute minds of Europe have long been successfully employed, that we will not linger upon it with mere verbal criticism.
We can not present a more striking illustration of the change in the composition of inks about the time of the invention
