A favorite method of making impressions was that of branding. Virgil, in the third book of the Georgics, tells us of its application to cattle. The old laws of many European states tell us of its application to human beings. The cruel practice was kept up long after the invention of typography. During the reign of Edward VI, of England (1547–1553), it was enacted that, “whosoever, man or woman, not being lame or impotent, nor so aged or diseased that he or she could not work, should be convicted of loitering or idle wandering by the highwayside, or in the streets, like a servant wanting a master, or a beggar, he or she was to be marked with a hot [p039] iron upon the breast with the letter V [for vagabond], and adjudged to the person bringing him or her before a justice, to be his slave for two years; and if such adjudged slave should run away, he or she, upon being taken and convicted, was to be marked upon the forehead, or upon the ball of the cheek, with the letter S [for slave], and adjudged to be the said master’s slave forever.” With these evidences before us of long continued practice in various methods of engraving and stamping, and of a fair knowledge of some of the advantages of movable letters, the question may be asked, Why did the world have to wait so long for the invention of typography? This question is based on the assumption, that the civilization of antiquity was capable of making and preserving the invention which was missed through accident or neglect. Here is a grave error. The elements of an invention are like those of a chemical mixture. All the constituents but one may be there, exact in quantity and quality, but, for the lack of that one, the mixing of the whole in a new form cannot be accomplished. Failure in one point is entire failure. The ancients failed in many points. They were destitute of several materials which we regard as indispensable in the practice of printing. They had no ink suitable for the work. Pliny and Dioscorides have given the formulas for the writing ink that was used by Greek and Roman scribes during the first century. Pliny says that the ink of book-writers was made of soot, charcoal and gum. He does not say what fluid was used to mix these materials, but he does allude to an occasional use of acid, to give the ink encaustic property and to make it bite in the papyrus. Dioscorides is more specific as to the quantities. He says that one ounce of gum should be mixed with three ounces of soot. Another formula is, one-half pound of smoke-black made from burned resin, one-half ounce each of copperas and ox-glue. Dioscorides further says that the latter mixture “is a good application in cases of gangrene, and is useful in scalds, if a little thickened, and [p040] employed as a salve.” From this crude recipe one may form a correct opinion of the quality of the scientific knowledge then applied to medicine and the mechanical arts.