By HENRY  G. FERGUSON.

INTRODUCTION.

                                                                                                                     

Natural graphite may  be  either  crystalline  or  amorphous.  Crys- 

talline  or flake  graphite is  commonly  understood  to mean  graphite 

in  crystals  of sufficient size  to be visible  to  the naked  eye; much  of 

the so-called amorphous graphite shows a  crystalline structure under 

the microscope.  Crystalline graphite occurs either in  veins, as in the 

Ceylon deposits,  or as flakes disseminated through the country rock, 

as in many of the deposits in the United States.

Most deposits of amorphous graphite are the result of the alteration 

of  coal bed's by the intrusion of igneous rocks.  Amorphous graphite 

s  also made artificially by means of the electric furnace.

The peculiar physical properties of graphite infusibility, chemical 

inertness, high conductivity,  extreme softness,  and low specific grav- 

ity fit it for a large number of uses, such as the manufacture of cruci- 

bles  and other refractory products, lubricants,  "lead" pencils, paint, 

oundry facings, as a preparation to loosen boiler scale,  as a polish for 

gunpowder,  and in  various  types  of  electrical  work.  Of  these  uses 

the manufacture  of  crucibles  takes  by far  the  greatest share  of  the 

total output.