Forty Centuries of Ink / Or, A chronological narrative concerning ink and its backgrounds, introducing incidental observations and deductions, parallels of time and color phenomena, bibliography, chemistry, poetical effusions, citations, anecdotes and curiosa together with some evidence respecting the evanescent character of most inks of to-day and an epitome of chemico-legal ink.

by David Nunes Carvalho

"Get the impregnation of saturn made with vinegar, distilled as I have shewn before, or else dissolve so much salt of saturn as a quantity of water is able to receive: write on paper with a new pen dipt in this liquor, take notice of the place where you writ, and let it dry, nothing at all will appear.

"Write upon the invisible writing with the ink made of burnt cork, and let it dry, that which you have writ will appear as if it had been done with common ink.

"Dip a little cotton in the first liquor made of lime and orpin, but the liquor must be first settled and clear; rub the place you writ upon with this cotton and that which appeared will presently disappear, and that which was not seen will appear.

ANOTHER EXPERIMENT.

Take a book four fingers breadth in bigness, or bigger if you will: write on the first leaf with your impregnation of saturn, or else put a paper that you have writ upon between the leaves; turn to t' other side of the Book, and having observed as near as may be the opposite place to your writing, rub the last leaf of the book with cotton dipt in liquor made of quick- lime and orpin, nay and leave the cotton on the place clap a folded paper presently upon it, and shutting the book quickly, strike upon it with your hand four or five good strokes; then turn the book, and clap it into a press for half a quarter of an hour; take it out and open it, you'll find the place appear black, where you had writ with the invisible ink. The same thing might be done through a wall, if you could provide something to lay on both sides, that might hinder the evaporation of the spirits.

REMARKS.

"These operations are indeed of no use, but because they are somewhat surprizing, I hope the curious will not take it ill, that I make this small digression.

"It is a hard matter to explicate well the effects I have now related, nevertheless I shall endeavour to illustrate them a little, without having recourse to sympathy and antipathy, which are general terms, and do not explicate nothing at all; but before I begin, we must remark several things.

"The first is, that it is an essential point to quench the coal of cork in aqua vitae, that the visible ink may become black with it.

"Secondly, that the blackness of this ink does proceed from the fuliginosity or sooty part of the coal of the cork which is exceeding porous and light, and that this fuliginosity is nothing but an oil very much rarefied.