"BLACK-LEAD" PENCILS AN EXCELLENT PEN SUBSTITUTEUNDER CERTAIN CONDITIONS--ITS COMPOSITION-"BLACK-LEAD" CONTAINS NO LEAD, HENCE THE NAME IS MISAPPLIED--THE DISCOVERY OF ITS PRINCIPAL SOURCE OF SUPPLY AN ACCIDENT--A DESCRIPTION OF HOW IT IS MINED--TREATMENT BEFORE BEING INTRODUCED INTO THE GROOVED WOOD--USE OF RED AND BLACK CHALK PENCILS IN GERMANY, 1450--THEIR USE IN MEXICO IN EARLYTIMES--WHO MANUFACTURES LEAD PENCILS--EMPLOYMENTOF THE COMPOSITION OF LEAD AND TIN IN MEDIAEVAL TIMES--BAVARIAN GOVERNMENT IN 1816 A MANUFACTURER OF LEAD PENCILS.
THE black-lead pencil, under many circumstances, is a very useful substitute for the pen, in that it requires no liquid ink for marking the characters on paper or other materials. The peculiar substance which fills the central channel of the stick of cedar has the property of marking when it touches paper;and, as the marks thus made are susceptible to easy removal, a pencil of this kind is available for purposes which would not be answered by the use of pen and ink.
The substance misnamed "black-lead" contains NOLEAD and is a carburet of iron, being composed of carbon and iron. It generally occurs in Mountain districts, in small kidney-shaped pieces, varying in size from that of a pea upwards, which are interspersed among various strata, and is met with in different parts of the world.
Its principal source of supply until about 1845, when it became exhausted, was the Borrowdale mine in Cumberland, England, which was discovered in 1564. About 1852 a number of mines were opened containing this substance in Siberia and from which place the best products are now obtained.
The accidental discovery of this mineral at Borrowdale was during the reign of Queen Elizabeth who made many inquiries about it. The name of this mineral was locally known as wad (graphite). So valuable was it regarded that it commanded a very high price, and this price acted as in inducement to the workmen and others to pilfer pieces from the mine. For a number of years scenes of great commotion took place, arising out of these depredations; and the result was that the proprietors adopted such stringent rules that hardly anything was known of the internal economy of the mine till about sixty years ago, when Mr. Parkes gave a description of it, from which I may condense a few particulars.
The mine is in the midst of a mountain about two thousand feet high, which rises at in angle of about 45 degrees; and, as that part of the mine which has been worked during the last century is near the middle of the mountain, the present entrance is about a thousand feet from the summit. The opening by which the workmen enter descends by a flight of steps; and in order to guard the treasure within, the proprietors have erected a strong brick building of four rooms, one of which is immediately over the entrance into the mine. This entrance is secured by a trap-door, and the room connected with it serves as a dressing-room for the men when they enter and leave the mine. The men work in gangs, which relieve each other every six hours, and when the hour of relief comes, a steward or foreman attends the dressing-room to see the men change their dresses as they come up one by one out of the mine. The clothes are examined by the steward to see that no black-lead is concealed in them; and when the men have dressed they leave the mine, making room for another gang, who change their clothes, enter the mine, and are fastened in for six hours. In one of the four rooms of which the house consists there is a table, at which men are employed in sorting and dressing the mineral. This is necessary, because it is usually divided into two qualities, the finest of which have generally pieces of iron-ore or other impurity attached to them, which must be dressed off. These men, who are strictly watched while at work, put the dressed black-lead into casks holding about one hundred-weight each, in which state it leaves the mine. The casks are conveyed down the side of the mountain in a curious manner. Each cask is fixed upon a light sledge with two wheels, and a man, who is well used to the precipitous path, walks down in front of the sledge, taking care that it does not acquire momentum enough to overpower him. When the cask has been thus guided safely to the bottom, the man carries the sledge up hill upon his shoulders, and prepares for another descent.
Up to about the middle of the eighteenth century the mine was opened only once in seven years, the quantity taken out at each time of opening being such as was deemed sufficient to serve the market for seven years;but when, at a later period, it was found that the demand was increasing and the supply decreasing, it was deemed necessary to work the mine six or seven weeks every year. During the time of working, the mine is guarded night and day; and when a quantity sufficient for one year's consumption has been taken out, the mine is secured until the following year.
Several hundred cartloads of rubbish are wheeled into the mine, so as to block up the entrance completely;and this rubbish acts as a dam to prevent the springs and land waters from flowing out, so that the mine gradually becomes flooded.
When the Year's mining is concluded, the barrels of black-lead are brought to market, and the mode of effecting the sales was described by Dr. Faraday some years ago to be as follows: A market is held on the first Monday of every month at a house in London, where the buyers, who are generally only seven or eight in number, examine each piece with a sharp instrument to ascertain its hardness, those which are too soft being rejected. The person who has the first choice pays 45s. per pound, the others 30s.
But, as there is no addition made to the first quantity in the market, the residual portions are examined over and over again until they are exhausted. At one time the annual sale was said to amount to the value of L40,000 per annum, but it has been greatly reduced since.
