Page:The History of Ink.djvu/54

48 and European mouths has smoothed and softened itself into a form suggestive of the origin of Maurus and Mauritania.]

Now, without coming to a positive conclusion on this subject, we feel authorized to pronounce what appears to be a reasonable opinion, derived from all the facts which we have just placed before the reader,—that the introduction of writing-paper among Europeans, was the occasion and cause of the invention and general employment of modern writing-ink by them.

The fact that the vegetable astringents form a deep or bluish black color, when combined with a salt of iron, had been known from time immemorial. Among the Romans, the atramentum sutorium,—"shoemaker's ink,"—was applied to a solution of sulphate of iron employed by them, as it is even to this day, by workers in leather, to blacken the surface of that material. This it does by uniting chemically with the tannin and gallic acid, by which the hide was converted into leather, whose blackened particles are therefore essentially identical with modern ink. The "copperas-water" is to be found in every shoemaker's shop, where it is used to color the cut edges of the heels and the rest of the soles.