218 BULLETIN 42, UNITED STATES NATIONAL MUSEUM. 



comes in contact with. It differs from the diamond in being very soft 

 and crystallizing in the hexagonal system. It occurs in the older crys- 

 talline rocks. 



Graphite is used for a variety of purposes. The manufacture of cru- 

 cibles and other fire-resisting articles and stove polish consumes two- 

 thirds of the total used. Small amounts are used for lubricators, paint, 

 polishing material, and lead pencils. A single specimen is shown here ; 

 others will be found with the manufactured articles. 



(1) Coarsely crystalized, iu cfiiartz aud mica, a characteristic specimen of dissemi- 

 nated ore requiring dressing to separate the graphite from the gangue. Ticonder- 

 oga, Essex County, New York. (37825.) 



APPLICATION OF GPAPHITE. 



The crude graphite and manufactured articles from Bloomingdale, 

 Passaic County, New Jersey, are illustrated by six specimens : 



(1) Sample from main shaft of vein, 20 feet wide. (56272.) 



(2) Dry lubricator, for ordinary machinery. No. 10. (56273.) 



(3) Dry lubricator, for heavy bearings. No. 50. (56274.) 



(4) Brush silver facing, for foundry uses. No. 60. (56275.) 



(5) Stove polish. No. 6L (56276.) 



(6) Very fine, for electrotypers, lead pencils, etc. No. 90. (56277. ) 



The following specimens illustrate prepared graphite manufactured 

 by the Pennsylvania Mining aud Manufacturing Company, Philadel- 

 phia, Pennsylvania. 



(1) Crucible graphite. (32465. ) 



(2) Pure lubricating. (32460.) 



(3) Lubricating " Excelsior." (32461.) 



(4) Shot glaze. (32462.) 



The following series of specimens shows three characteristic varieties 

 of graphite from the mines of the Dominion of Canada Plumbago Com- 

 pany, in Buckingham, Province of Quebec, Canada, the material as pre- 

 pared for various uses aud articles manufactured from this graphite, 

 some of which have been subjected to severe practical tests : 



(1) Foliated, characteristic and very handsome. (51007.) Composition: 



Per cent. 



Carbon 99.675 



Volatile matter 0.178 



Ash 0.147 



(2) Columnar and granular, massive. (59976.) Composition: 



Per cent. 



Carbon 97.626 



Volatile matter 0. 594 



Ash 1.780 



(3) Disseminated in a decomposed rock. (.59977.) Composition: 



Per cent. 



Graphite 23.798 



Soluble rock matter 21.285 



Insoluble rock matter 53.741 



lygroscopic water 1. 176 



(5) Powder glaze. (32463.) 



(6) Pencil graphite. (32466.) 



(7) Electrotyping graphite. (32464.) 



