The Lead Pencil

New Zealand Tablet, Volume XXXIV, Issue 6, 8 February 1906, Page 20

The Lead Pencil

The six lead pencil factories in the United States employ more than 2000 persons, pay £140,000 per annum in wages, turn out 12,000 gross daily, the annual output being worth close on £500,000. These factories make as many pencils as all of Europe combined, and yet despite the importance of this industry (says an American exchange), there are few who can tell how this indispensable little article is made. Structurally speaking, the lead pencil consists of an outer shield or covering and of an inner piece of round solid graphite. The wood, which is of prime importance, must be durable and compact, straight grained and soft, so that it may be alike easy to polish and whittle; if it is fragrant, so much greater its value. Now of all the trees in the world our Virginia or red cedar, which grows so luxuriantly in the South, particularly in Alabama and Florida, is the only one whose wood meets all these requirements. Our pencil manufaciurers own their own cedar mills, but the European makers, much to their dislike, are obliged to purchase their pencil covering from us. In order to place themselves on an equal footing an attempt was made to transplant the Virginia cedar. Germany devoted 100 acres to that purpose some forty years ago, but the climate proved unfavorable and a few stunted trees with wood as hard as oak, proclaimed the experiment a rank failure. On the other hand, we go to foreign markets for our graphite, the best qualities of which come from Eastern Siberia, Mexico, Bohemia and Ceylon. Our largest factory, taking advantage of the cheaper labor market abroad, has all of its graphite prepared in Germany and sent here ready for use. Nor is cheap labor the only consideration, for the German graphite makers, like, the wood carvers of Switzerland and the toy makers of Nuremburg, follow the trade from father to son ; take to it q\uite naturally and leave the rest of the world behind in expertness. . Pencil lead consists of a mixture of clay and graphite, both undergoing a careful and separate treatment before they are united. The raw graphite, after being reduced to a fine powder in a mortar, sifted and freed from impurities by mineral acids, is washed and fired to a bright red heat. The next step is to add water to the preparation, and pour it into a vat, where the heavier particles sink. From this vat the water carries the lighter particles into another at a lower level, and then on into one or two more, where the heavier particles drop to the bottom and .the finer particles are carried over. The 'graphite drawn from the last vat in .the series is in a state of extremely fine division, and its value reserves it for use in the best pencils only. The clay, purged of sand and iron, goes through somewhat the same process, and then it is mixed with the graphite, the proportion varying all the way fiom equial parts to two of clay for one of graphite— the amount of clay depending strictly on the degree of hardness or softness wanted for the pencil leads. When the particles of cray and graphite are thoroughly incorporated and ground together they are placed in bags and squeezed to the consistency of dough by a hydraulic press. The formless substance, ready to be shaped into pencil rods, is forced by a piston in continuous threads through the many apertures of a strong upright brass cylinder, each of the apertures being of exactly the same size as the leads that are to be fitted in the pencils. The long threads of graphite are received and arranged on straight grooves of. a wide board and left to harden until they become &s stiff as rods. Afterward they are cut into requisite- pencil lengths— seven inches as a rule— packed witii, charcoal ia a covered crucible and submitted to a higll. furnace heat.