The fact of the English Government having considered it expedient rigorously to prohibit the export of black lead in any other form than that of leadpencils goes to prove of what importance these mines and the manufacture of leadpencils in connexion with them was to England. In spite of the fact however that the mines only remained open for six weeks in the year and that no blacklead might be exported from them, the working of the mines, continued as it was for upwards of a century, at last began to have the effect of diminishing the yield, until at last nothing was to be obtained from them but an inferior and impure material no longer adapted as before for the manufacture of pencils. In order to protect themselves from the consequences of a failure of the Cumberland blacklead mines, the English strenuously sought in every direction for new blacklead deposits, but down to the present day without the desired success. There remained therefore nothing but to look about for some means whereby the impure refuse still obtainable could be purified. The process invented for this purpose consisted of first grinding the blacklead to powder as soon as it came out of the mine, then purifying it as much as possible from foreign substances by chemical means and finally compressing it by means of a press in such a manner that the mass could be just as easily cut as the pure Cumberland blacklead used to be. However notwithstanding all the appliances of art and science were brought to bear upon the subject and spite of every exertion to render this composition perfect, the English have not hitherto succeeded in producing any material capable of replacing the natural blacklead as obtained from the Cumberland mines. These circumstances operated as an inducement to search for a substitute, which would admit of a greater economy in the use of blacklead. Experiments were made in England with this view and various substances such as glue, isinglass, tragacanth, gum &c. were tried for the purpose of cementing and consolidating the earthy blacklead into a firm mass. But none of these means succeeded. Subsequently it was attempted to improve the blacklead by melting it with minerals, compounding it with 30 or 40 per cent of sulphur. But this made the blacklead too brittle and the pencils made by this process would hardly mark at all. At last mixing with antimony was tried, which certainly yielded a composition in outward appearance very similar to the pure blacklead, but which proved to be but an unsatisfactory writingmaterial.