The kind of pencil called "crayon" is a mixture of some kind of earth with a coloring substance. The earth employed is sometimes chalk, and at other times pipe-clay, gypsum, starch-flour, or ochre. The coloring substance is yellow ochre, mineral yellow, chrome, red chalk, vermilion, indigo--indeed, any of the usual dry colors, according to the tint required. Besides the earth and the color, there is a gummy liquid required to combine them together; gum arabic, gum tragacanth, and in some cases oil, wax, or suet, are used as the third ingredient. The crayons here alluded to are employed rather for drawing than for writing, but they obviously belong to the class of pencils in their mode of action. The ancients drew lines and letters with wooden styles, and afterward an alloy of lead and tin was used. Pliny refers to the use of lead for ruling lines on papyrus. La Moine cites a document of 1387 ruled with graphite. Slips of graphite in wooden sticks (pencils) are mentioned by Gesner, of Zurich, in 1565; he credits England with the production. They are doubtless the product of the Borrowdale mine, then lately discovered. In the early part of the seventeenth century black-lead pencils are distinctly described by several writers. They are noticed by Ambrosinus, 1648; spoken of by Pettus, in 1683, as inclosed in fir or cedar. Red and black chalk pencils were used in Germany in 1450; in fact, fragments of chalk, charcoal, and shaped sticks of colored minerals had been in use since times previous to all historic mention. When Cortez landed in Mexico, in 1520, he found the Aztecs using graphite crayons, which were probably made from a mineral found in Sonora. The firm of A. W. Faber are the largest manufacturers of lead pencils in the world. They have compiled a history of this implement of handwriting which they have permitted me to use in the story which follows. The lead pencil is an invention of modern times, and its introduction may deservedly be ranked with the large number of technical innovations in which more especially the last three centuries have been so rich; nor can it be denied that pencils have played an important part in the diffusion of arts and sciences and in facilitating study and intellectual intercourse. To the classic ages and their art the pencil, and in general every application of lead as a writing material, was entirely unknown, and it was not till the advent of the middle ages that it began to be used for this purpose. This lead, i. e. metallic lead, however, was in no way equivalent to the graphite or black-lead of our pencils, which are only honored with the prefix of "lead," owing to the leaden color of the writing done with them.