The name pencil is applied to a small hair brush used by artists, and also to a slender cylinder of black lead inclosed in a case, and used for drawing or writing. Hair pencils are made from the hair of the camel, the badger, the squirrel, the goat, and some other animals. A small bundle of hairs, with the points in one direction, is tied with strong thread at the root ends, and the points having been temporarily secured, the bundle is introduced at the wide end of a piece of quill tube, previously softened by moisture, when the thickness of the roots and of the binding thread prevents the bundle from passing quite through, while the contraction of the tube in drying holds the tuft securely. The broad end of the quill forms the socket for a holder of cedar wood. Some skill is required in tying and inserting the bundle of hair, for if pinched too tightly, the hairs spread out, instead of forming a fine point, and if not sufficiently pinched, they fall out. Hair pencils are made from the size of a crow or pigeon-quill to that of a swan. When larger pencils are required, tubes of tin-plate are used, with the stick firmly secured therein.

Lead pencils of the best kind are made of slender four-sided threads, which were formerly cut by means of a saw from solid pieces of plumbago. These threads were calcined in close vessels at a bright red heat, which imparts brilliancy and softness to the stroke of the pencil. The excellence of the mineral, as obtained from the mine of Borrowdale in Cumberland, has long given celebrity to English pencils; and the crayons d'Alepeterre are in great esteem on the Continent. Mines of plumbago have been discovered in the United States of America, the most important of which is that at Sturbridge in Massachusetts. The mineral, however, is coarse in texture compared with that of Borrowdale. The method of preparing it is as follows:—It is pulverized, purified by sifting, and the powder condensed into thin sheets by means of intense pressure; a welding property discovered by Mr Brockedon some years ago, and now brought into general use, owing to the threatened exhaustion of the Cumberland mine, and also for using up the waste material of the manufacture. The plan is to reduce the plumbago to a very fine powder, then to exhaust the intersticial air, and to subject the powder to the force of a hydrostatic press. In this way coherent masses are formed as dense and as useful as the original plumbago. Slices having been cut from a block thus formed; the edge of a slice is inserted in a channel in the cedar-holder, and being cut off, the process is repeated until the groove is filled; or the lead may be cut into square threads, which, after being rounded by passing through circular holes cut in pieces of ruby, are made into the proper lengths for ever-pointed pencils. The cedar for the handles is imported chiefly from South America.

The costliness of the best lead pencils has led to many attempts to economize the material by the introduction of other substances. The most successful attempt of this kind was made towards the end of the last century by a Frenchman named Conté. By mixing pure clay in various proportions with black lead in powder, and also with various coloured earths, he was able to produce pencils and crayons of various degrees of hardness and tint. The clay was carefully washed, and diffused in tubs of river-water, and after settling for two minutes, the milky liquor was drawn off by a syphon into a second tub, and the finest particles thus collected formed a soft and plastic mass fit for use after having been dried on linen filters. The powdered plumbago was calcined in a crucible to nearly a white heat, after which it was mixed with the clay in varying proportions; a fine hard pencil being produced by two parts of clay to one of plumbago, and a softer pencil by equal parts of each. The powders, when mixed, were triturated with water, and ground on a porphyry slab, and when of the proper consistence, the paste or dough was pressed into grooves in a board, previously greased, and another board screwed down upon it; in this condition the air could act only on the ends of the pencils in the grooves, and these shrinking as they dried, the air gradually entered and dried the whole lengths. The drying was completed in an oven at a moderate heat, after which the threads were hardened by heating them in a crucible with sand or charcoal powder, the heat being regulated according to the degree of hardness required. If intended for very fine work, Pendulum such as architectural drawing, the threads were heated, and then immersed in melted wax or suet, nearly boiling hot. It was also found that different degrees of hardness could be obtained by plunging the pencils in various saline solutions, such as that of sulphate of soda, more or less concentrated. The lead thus prepared was then placed in the cedar cases in the usual way.

It has been asserted that the moderate admixture of clay with powdered plumbago takes away that unpleasant glistering property which we sometimes see in pencil-drawings, and does not diminish the blackness. By the addition of lamp-black to the clay and plumbago, pencils of every shade of black have been produced. The mixture must be calcined with exclusion of air, and afterwards made into a paste. The hardest pencils of the architect are made of lead melted with antimony and a small proportion of mercury.

The cheapest pencils are made with black lead in powder mixed with melted sulphur, and poured into holders of wood, of reeds, or of rushes. Common carpenters' pencils are made in this way. The graphitic modification of carbon deposited in the interior of coal-gas retorts is also used in the manufacture of lead-pencils. Gum-arabic, resin, sulphuret of antimony, fusible glass in powder, and other substances, are all used in making cheap pencils.

Slate pencils are made of slate for writing on slabs of the same material. Slate pencils have been made artificially by mixing slate powder with vulcanized india-rubber for writing on slabs of the same material, which are not liable to break; but the objection to the frequent handling of vulcanized india-rubber is the unpleasant smell occasioned by the sulphur.