This sifting process completely eliminated all but lampblack, madder and indigo in some form as a permanent "added" color pigment. Lampblack, which is we know forms the basis of "Indian" ink, is not soluble and requires a very heavy gummy vehicle to prevent its immediate precipitation, and while it could have been used in combination with tanno-gallate of iron as an ink, the fact that it was possible to chemically remove the ancient inks which remained black, was a sufficient demonstration that this carbon substance, which is not affected by chemicals, either as contained in the fluid ink or as dusted on after writing, could have formed no part of the ancient tanno-gallate of iron inks. Madder is mentioned as of very ancient times and was cultivated in Europe as early as the tenth century; its addition to an iron and gall ink is said to be an invention of the year 1855; it is certain, however, that it was used for a like purpose as early as 1826, and a fair presumption that it was frequently employed in some form during the preceding four centuries. It has under certain conditions very lasting properties as the madder-dyed cloths found wrapped around Egyptian mummies demonstrates, but does not assist the tanno-gallate of iron to retain its black color; on the contrary it seems to lessen this quality. That indigo for added color was employed by ink manufacturers in the eighteenth century is shown by the formulas appearing in the literature of that time. It was used alone as an ink long before, as well as contemporaneously with, those of the tanno-gallate of iron family. Its lasting properties are most remarkable if it be true that, used as a dye, there is still in existence specimens of it on cloth five thousand or more years old. The history of its use ALONE as an ink is difficult to ascertain back of a certain period; the writer has several specimens of it, one written in 1692 whose color is a green blue; another written about a century ago is believed to be as bright blue as the day it was placed on the paper; from 1810 to 1850 it was in common use particularly in hot climates where it was "home-made." Consequently if the old "gall" inks contained a lasting added color, indigo must have been the one, Dr. Stark whose investigations along this line for twenty-three years have already been cited has said that he preferred for his own use an ink composed of galls, sulphate of indigo and copperas (sulphate of iron); this means a tanno-gallate of iron ink with indigo for "added" color. Like formulas calling for different proportions of constituents both before and after his time in England and the continents of Europe and America are to be found in considerable number, proving that its use was more or less constant in this respect. To determine, then, whether or not the blacker specimens of the ancient writings contained indigo in any of its forms was most important, and the plan adopted most simple. Specimens of writing