The period when this semi-metallic substance was introduced, for the purpose for which it is now applied, cannot with certainty be ascertained, as no record is found of the transaction: by the common expedient of inference, however, we certainly may conclude, it was in very remote ages; for transcribers of MSS. upwards of one thousand years ago, used a substance somewhat resembling it in effect. But, perhaps, the antiquity of the use of black-lead pencils cannot be so well determined from diplomatiques, as their frequency might be proved from mineralogical writers. The first mention of this discovery occurs in the works of Gesner, who, in his About thirty years afterwards, CÆsalpinus gave a more perfect account of it:—he says it was a lead-coloured, shining stone, as smooth as glass, and appeared as if rubbed over with oil; it gave to the fingers an ash-grey tint, with a plumbeous brightness; and, he adds, pointed pencils were made of it, for the use of painters and draughtsmen. A closer description of the substance than this cannot be discovered. Somewhere about three years afterwards, a still more perfect description was furnished by Imperatis; who says, “It is much more convenient for drawing than pen and ink, because the marks made with it appear distinct upon a white ground, also, in consequence of its brightness, show themselves on black, and can be preserved or rubbed out at pleasure. This mineral is smooth, appears greasy to the touch, and has a leaden-colour, which it communicates with a metallic brightness. It can resist, for a long time, the strongest fire, and even from it requires more hardness; it has, in consequence, been thought to be a species of talc. This, in the arts to which it is applied, is a property which greatly enhanceth its value, being manufactured into crucibles, &c., with clay. These vessels are capable of enduring the strongest heat of a chemical furnace.” Sometimes this lead is foliaceous, and may be crumbled into small pieces or scales; but frequently found denser and more strong. This latter is what writing pencils should be made of; but the former being more frequently found, and, also, coming from the refuse of Robinson, in his Essay towards a natural History of Westmoreland and Cumberland states, that, at first, the country people round Keswick marked their sheep with black-lead. Afterwards, they discovered the art of employing it in their earthenware, and also to preserve iron from rust. The same writer says, the Dutch use it in dyeing, to render black more durable; and that they buy it in large quantities for that purpose. But their application of it for dyeing, we should consider as highly questionable. The mode of eradicating black-lead by means of an elastic gum, called caoutchouc, or, Indian-rubber, was, we have been informed, first discovered in England somewhere about sixty years ago. |