Page:The American Cyclopædia (1879) Volume VIII.djvu/173

 GRAPHITE it was to be fired. This was superseded by canister shot, in which the balls are confined in a canister of iron plate. The term grape shot is now applied to an assemblage of iron shot fast- ened around a metallic spindle, giving the ap- pearance of a bunch of grapes. The shots fly asunder as they leave the gun, and are very destructive at short distances. GRAPHITE (Gr. ypafaiv, to write), a mineral commonly called black lead or plumbago, but which titles are incorrect, as it contains no lead. Its composition is similar to that of an- thracite coal, containing usually from 90 to 95 per cent, of carbon, with from 4 to 10 per cent, of iron, and traces of silica, alumina, lime, and magnesia. Specimens have been found in Ceylon said to contain 98*55 per cent, of car- ' Dn. It occurs in beds and imbedded masses id laminae, in granite, gneiss, mica schist, and illine limestone, and sometimes in green- le. It is sometimes the result of alteration heat of the coal formation, and is an ordi- iry artificial product of the destructive dis- lation of coal in the retorts of gas works. It found in nature in both a crystalline and )rphous condition, opaque, of a metallic, si-gray color and lustre, and giving a pecu- r, shining, greasy streak on paper. Its spe- ic gravity is 2 '09, rising somewhat above lis as impurities increase. Its hardness ranges fcween 1 and 2. Crystallized graphite occurs six-sided tables, belonging to the hexagonal stem, cleaving perfectly in the direction of base, and having the basal planes striated llel to the alternate sides ; but the mineral more commonly found in foliated or granular It is found associated with olivene and ihene at Ticonderoga, N. Y., and in beds of leiss at Sturbridge, Mass., usually in a scaly id granular, but sometimes approaching a illine form. It is also found at North )kfield, Brimfield, and Hinsdale, Mass., at andon, Yt., and at Grenville, Canada, where jcurs near Amity, Orange co., N. Y., in white nestone, associated with spinel, chondrodite, id hornblende ; at Eossie, 4 St. Lawrence co., nth iron ore, and in gneiss; in Bucks co., ., near Attleboro, associated with tabular >ar, pyroxene, and scapolite, and also in sye- ite at ManselPs black-lead mine near the le locality. There is a large deposit at St. John, N. B. The mine at Borrowdale in imberland, England, has long been celebra- " for yielding graphite of a superior quality >r making black-lead pencils, one of its prin- uses. The mine has been known since le time of Queen Elizabeth, and probably irnished the first lead pencils ever made, as leir invention cannot be traced back as far the discovery of the mine. It is in a moun- lin, 8 m. S. of Keswick, 2,000 ft. high. The ineral occurs in small nests in trap. The are about the size of the fist. The mine le so valuable as to be an object of plun-, being reached underground from neigh- GRASSE 165 boring mines, and being once forcibly taken possession of at the surface. The graphite was of so pure a quality that it required but little preparation for the market; and much of it was sawed up in its natural state for pencils. The mine is now nearly exhausted, and has not been worked for many years. Graphite has been found in Germany, France, Austria, and South America, and in enormous masses in N. E. Siberia. Besides furnishing a material for writing pencils, it is used for making cru- cibles, and linings for small furnaces; as an ingredient in lubricating compounds for ma- chinery ; for giving a smooth surface to the moulds of metal castings, and for polishing stoves and iron castings generally ; and also for a coating to wax or other impressions of ob- jects designed to be electrotyped, for the pur- pose of forming a good conducting surface for the galvanic current. It has also been em- ployed by Graham as a diaphragm in his dif- fusiometer or instrument for observing the comparative rate of diffusion of gases. (See CETJOIBLE, and PENCIL.) GRAPTOLITES (Gr. -yp&fetv, to write, and Woe, stone), a genus of fossil acalephs, of as many as 20 species, found only in the Silurian rocks, abounding particularly in the slates of the Hud- son river group. So numerous are these early forms of zoophytes in the Llandeilo rocks of Europe, that it has even been thought prob- able that the carbonaceous character of the slates was owing to the abundance of their re- mains. As found in the black slates, their sil- 1. Graptolithus Logani, showing the centre of a branching group. 2. Portion of a branchlet. 3. Same, much en- larged. 4, 5. Forms of Phyllograptus typus. 6. Graptoli- thus pristis. 1. Young of a graptolite. very forms are obscurely retained, and the fos- sils may easily be mistaken for impressions of plants. They are long and slender, resembling some algse, as well as the feather part of a quill, whence their name. When found in cal- careous strata their forms are more distinct. Their nearest living analogues are the sea firs or sertularians, of which the species inhabit muddy sediment, such as the black slates must once have been. GRASS CLOTH. See RAMIE. GRASSE, La, a town of 8. E. France, in the department -of Alpes-Maritimes, 18 m. W. of Nice; pop. in 1866, 12,241. It was formerly the seat of a bishop, has a Gothic cathedral, a college, a public library, and large manufacto- ries of essences and perfumes, soap, and silk goods. In the vicinity are quarries of marble and alabaster, and extensive olive groves.
 * is associated with sphene and tabular spar. It