Assuming a second premise was to assert that the inks employed in the writing of these documents were "straight" or possessed some "added" pigment or color. Again, the vehicles to hold the particles or possibly preserving substances, might be factors. All literature possible referring to ink formulas was examined to ascertain the names of materials recommended or formerly "added" to gall inks, because if the pristineness of the blacker inks was due to the added pigment it was a safe proposition that it was still existent in the ink, and that if it could be discovered part at least of the problem would be, simplified. The "added" color compounds, excluding those of the aniline family which pertain to the more modern ink compositions, are of two classes: those possessing tannin and color-yielding materials and those containing only a color-yielding material. Many of the first class have been used in the manufacture of ink both with infusions of nut-galls or alone, while but very few of the second class have been used for either purpose. The decomposing action of light, oxygen and moisture on many of each class placed them beyond the purview of consideration, while the dates of the discovery and the fact of the small percentage of tannin contained in others permitted them also to be discarded. For instance: vanadium, which is fairly permanent, was discovered only in 1830; chanchi, the ink plant of New Granada discovered in the sixteenth century, possessing excellent lasting qualities, does not assimilate perfectly with other constituents used in the manufacture of ink, but is best when used alone; Berlin blue (prussian blue) is well spoken of, but was only discovered by accident in 1710 by Diesbach, a preparer of colors at Berlin; logwood, more used for this purpose than any other material, was first imported into Europe in the sixteenth century and causes a deterioration of the durable qualities of the tanno-gallate of iron; Brazil-wood and archil, and their allies, are exceedingly fugitive; bablah, the fruit of the acacia arabica, myrabolams, of Chinese growth, catechu, and sumac which though used in the time of Pliny, each contains a percentage of gallic acid too small to meet the requirements. Divi-divi, a South American product, came into use only at the end of the sixteenth century and has not stood the test of time.