1855.] Observations on the Graphite of Kumaon. 205 



degree of pressure be rendered nearly as compact as the best natur- 

 al Graphite, we should have been without any more good drawing 

 pencils. But the Graphite for grinding, though in small pieces, 

 must be pure, or otherwise the grinding mills become injured, besides 

 pencils made with it, being unfit for use. 



2 & 3. So also finely powdered Graphite is required for mixing 

 with fatty substances in order to diminish the friction of machinery. 

 It is equally evident, that this must be of the purest kind, or other- 

 wise the machinery in which it was prepared, or that to which it 

 was applied, would be equally injured. Thus also if Graphite, as an 

 infusible substance, is required for mixing with the more infusible 

 kinds of clay for making the best crucibles, the Graphite must be 

 without impurities, as these would diminish the melting point and 

 render the crucibles useless. 



4. The Graphite or Plumbago black-lead as it is commonly 

 called and used for polishing grates, is an impure substance, but if 

 it has sufficient lustre it may be applied to such a purpose ; it is 

 however always a low-priced article. 



Notwithstanding the unfavourable opinion entertained, by Mr. 

 Brockenden, of the Graphite from Kumaon, I again submitted to 

 him the specimens sent to the Exhibition of 1851 as well as those 

 which had been forwarded from Travancore. He considered both 

 as valueless, so Messrs. Eeeves, whose opinion I likewise asked, 

 accounted them " quite useless for the manufacture of black-lead 

 pencils." Messrs. Wolff of Church Street, Spital Fields who also 

 make pencils by first grinding and then condensing Graphite, took 

 a more favourable view of the specimens, inasmuch as they could 

 not conceive why pure specimens should not be found in the locali- 

 ties where both kinds had been collected. But they also observed, 

 that they could not use the specimens in the state in which they 

 had been sent, without damaging their machinery, and it would 

 take time and labour, costing of course a good deal of money in this 

 country, to separate the purer specimens from those which were 

 intermixed with quartz or ores of iron. 



Among the Travancore specimens, however, Messrs. Wolff ob- 

 serve, many are sufficiently pure for use, and if these were picked 

 out in India and sent separated from the pieces covered and inter- 



