92 GRAPHITE. 



berland mountaineers. In some years the net produce of 

 the six weeks 1 annual working of the mine, has amounted 

 to £40,000. 



In the United States, graphite occurs in large masses in 

 veins in gneiss at Sturbridge, Mass. It is also found in 

 North Brook field, Brimfield and Hinsdale, Mass. ; at Roger's 

 rock, near Ticonderoga ; near Fishkill landing in Dutchess 

 county ; at Rossie, in St. Lawrence county, and near Amity 

 in Orange county, N. Y. ; at Greenville, L. C. ; in Corn- 

 wall, near the Housatonic, and in Ashford, Ct. ; near Attle^ 

 boro, in Buck's county, Penn. ; in Brandon, Vermont ; in 

 Wake, North Carolina ; on Tyger river, and at Spartanburg, 

 near the Cowpens furnace, South Carolina. 



For the manufacture of pencils the granular graphite has 

 been preferred, and it is this character of the Borrowdale 

 graphite which has rendered it so valuable. At Sturbridge, 

 Mass., it is rather coarsely granular and foliated, and has 

 been extensively worked ; the mine yields annually about 

 30 tons of graphite. The mines of Ticonderoga and Fish- 

 kill landing, N. Y. ; of Brandon, Vt. ; and of Wake, North 

 Carolina, are also worked ; and that of Ashford, Ct., for- 

 merly afforded a large amount of graphite, though now the 

 works are suspended. 



The material for lead pencils, when of the finest quality, 

 is first calcined and then sawn up into strips of the requisite 

 size and commonly set in w r ood, (usually cedar.) as they ap- 

 pear in market. It is- much used now in small cylinders 

 without wood for ever-pointed pencil cases. Graphite of 

 coarser quality, according to a French mode, is ground up 

 fine and calcined, and then mixed with the finest levigated 

 clay, and worked into a paste with great care. It is made 

 darker or lighter and of dine rent degrees of hardness, by 

 varying the proportion of clay and the degree of calcination 

 to which the mixture is subjected; and the hardness is also 

 varied by the use of saline solutions. Lampblack is some- 

 times addded with the clay. 



A superior method in use at Taunton, Mass., where the 

 Sturbridge graphite is extensively employed, consists in 

 finely pulverising it, and then by a very heavy pressure ob- 

 tained by machinery, condensing it into thin sheets. These 



How are tbe best lead pencils made ? How are they manufactured 

 from the SturbridRe bed ] 



