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

TO DETERMINE THE DIRECTION OF THE GRAIN.— An easy but sure test to determine the direction of the grain in a sheet of paper, which will be found useful and worth remembering, is as follows:

For instance, the size of sheet is 17x22 inches. Cut out a circular piece as nearly round as the eye can judge; before entirely detaching from the sheet, mark on the circle the 17-inch way and the 22-inch way; then float the cut out piece on water for a few seconds; then place on the palm of the hand, taking care not to let the edges stick to the hand, and the paper will curl until it forms a cone; the grain of the paper runs the opposite way from which the paper curls.

ABSORBING POWERS OF BLOTTING PAPER.—Comparative tests as to absorbing powers of blotting can be made between sheets of same weight per ream by allowing the pointed corner of a sheet to touch the surface of a drop of ink. Repeat with each sheet to be tested, and compare the height in each to which the ink has been absorbed. A well-made blotting paper should have little or no free fibre dust to fill with ink and smear the paper.

TEST FOR GROUND WOOD.—Make a streak across the paper with a solution of aniline sulphate or with concentrated nitric acid; the first will turn ground wood yellow, the second will turn it brown. I give aniline sulphate the preference, as nitric acid acts upon unbleached sulphite, if present in the paper, the same as it acts upon ground wood, viz., turning it brown.

Phloroglucin gives a rose-red stain on paper containing (sulphite) wood pulp, after the specimen has been previously treated with a weak solution of hydrochloric acid.

About the end of the eighteenth century it became necessary to make special papers denominated "safety paper." Their manufacture has continued until the present day although much limited, largely because of the employment of mechanical devices which seek to safety monetary instruments. Such safety papers are of several kinds.

1. Paper made with distinguishing marks to indicate proprietorship, as with the Bank of England water mark, to imitate which is a felony. Or the paper of the United States currency, which has silk fibers united with the pulp, the imitation of which is a felony.

2. Paper made with layers or materials which are disturbed by erasure or chemical discharge of written or printed contents, so as to prevent fraudulent tampering.

3. Paper made of peculiar materials or color, to prevent copying by photographic means.

A number of processes may be cited: