172 REPORT OF NATIONAL MUSEUM, 1899. 



At Grenville the graphite occurs in a gangue consisting mainly of 

 pyroxene, wollastonite, feldspar, and quartz, while the country rock 

 is limestone. Blocks of graphite have been obtained weighing from 

 700 to 1,500 pounds. 1 



Graphite is also found in Japan (Specimen No. 34359, U.S.N.M.), 

 Australia (Specimen No. 62177, U.S.N.M.), New Zealand (Specimens 

 Nos 17796 and 64795, U.S.N.M.), Greenland (Specimen No. 65374, 

 U.S.N.M.), Guatemala (Specimen No. 33990, U.S.N.M.), Germany, 

 and in almost all the Austrian provinces, the most important and best 

 known deposits being those of Kaiserberg at St. Michel, where there 

 are five parallel beds occurring in a grayish black graphite schist, the 

 beds varying from a few inches to 6 yards. The only workable 

 deposit in Germany is stated to be at Passau in Bavaria. The material 

 occurs in a feldspathic gneiss, seeming to take the place of the mica 

 (Specimen No. 52050, U.S.N.M.). The beds have been worked chiefly 

 by peasants for centuries, and the output used mainly for crucibles. 2 



" lf ses , Graphite is used in the manufacture of "lead" pencils, 

 lubricants, stove blacking, paints, refractory crucibles, and for foun- 

 dry facings. In the manufacture of pencils only the purest and best 

 varieties are used, and high grades only can be utilized for lubricants 

 (Specimens Nos. 51608-51619, U.S.N.M.). For the other purposes 

 mentioned impure materials can be made to answer. In the manufac- 

 ture of the Dixon crucibles (Specimens Nos. 51598-51600, U.S.N.M.) a 

 mixture of 50 per cent graphite, 33 per cent of clay, and 17 per cent 

 of sand is used. 



Preparation. In nature graphite is usually associated with harder 

 and heavier materials, which it is necessary to get rid of before the 

 material is of value. In New York it is the custom to crush the rock 

 in a battery of stamps, such as are used in gold mining, and then 

 separate the graphite by washing, its lighter specific gravity permit- 

 ting it to be floated off on water, while the heavy, injurious constitu- 

 ents are left behind. Mica, owing to its scaly form, can not be 

 separated in this manner, and hence micaceous ores of the mineral are 

 of little if any value. 



An improvement in the manufacture of plumbago or graphite has 

 been described in a recent patent specification. Graphite, crushed and 

 passed through a sieve of from 120 to 150 meshes per inch, is stirred 

 into a saturated solution of alum or aluminum sulphate at a temperature 

 of 212 F. ; steatite is then added, and more water, if required. After 

 mixing, excess of water is evaporated until a consistency suited to 

 grinding in a chilled steel or other mixer is obtained. More graphite 

 may here be added; then, after thorough grinding, the material may 

 be compressed into cakes for household use, or is ready for the manu- 



1 Descriptive Catalogue of Economic Minerals of Canada, 1876, p. 122. 



2 The Journal of the Iron and Steel Institute, 1890, p. 739. 



