We have alluded to the _palimpsest_ manuscripts. This is the term applied to parchments that have been twice written upon,—the first writing being effaced to make room for the second. During the period commonly called “the dark ages,” the monks and other scribes, copyists or book-makers, were in the habit of effacing the letters from old manuscripts, in order to make a clean surface for a new writing. In this way was caused the deplorable destruction of an immense and an inestimably valuable amount of ancient literature, of Greek and Roman history, poetry, eloquence and philosophy, merely to make room for mass-books, and other works of stupid superstition and mis-directed devotion, or, of scholastic theology and philosophy, now long ago universally condemned and exploded. Within the past and present generation, however, the learned world has been delighted by the surprising recovery of some of these long-lost treasures, through the skilful and ingenious labors of the deservedly famous Cardinal Angelo Mai, and others, whose researches in the libraries of Rome, Milan, Padua, Naples, Florence, and other cities, have resulted in the restoration of inestimably precious writings, thus partially obliterated or obscured. Brande’s Dictionary of Literature, Science, and Art, gives a brief summary of the same general facts in the article “Palimpsest.” The fullest and most elaborate exposition of the composition and manufacture of Ink which we have been able to find, however, is in the great French “Dictionnaire des Arts et Manufactures,” by an association of distinguished _savans_, in two volumes, imperial octavo, Paris, 1853, article, ENCRE. But, of all articles and treatises on the subject, which we have examined, that in the English Penny Cyclopaedia has the merit of containing, if not the best and longest account, a very good and satisfactory one,—because it expresses all the essential facts in the fewest and best-chosen because perfectly intelligible words. As we do not attempt to furnish a text-book for ink-manufacturers, we do not transcribe in full, or translate, from these and other works of great value on this subject.