J. M. Stillman—Bernardinite, a new Mineral Resin. 57 
the experiments I have tried, the carbon has been of the soft 
American variety, with an average specific gravity of 1°55. 
Length of carbon, © S20 5i 24 SSS os et wee 17°5 em. 
Each side, - Py Pe ee Om i se 
Number an? of surface including ends, Sik 72 &m. 
Weight before coppering, ---.....---- -.- 21°1615 g. 
Weight after coppering, ..-......-....... 24°0410 “ 
Weighit:- of: ctpper,iigeic) sdolonlnceeicd 2°8795 “ 
Weight copper to each om. iy intl euneaease 4 0397 
In order to hn with the use of a reflector, I arrange the 
carbons + above as described in the Journal of Franklin 
Institute for May and June, 1878. 
he peculiar cup- shaped appearance of the positive carbon 
— to concentrate the light on the condenser. It is under- 
I am inclined to think a kaolin paste would be better than 
plaster for coating the carbons. The mage force used in all 
the experiments has been furnished by the Gramme machine, 
described in the Journal of the Franklin Institute already cit 
The use of projections aa illustration in lectures on Chem- 
istry and Physics h as _beco so general that I hope the sug- 
gestions in this paper may rove of some benefit. 
Purdue University, Lafayette, Indiana, April 18, 1879. 
Arr. X.—Bernardinite: a new Mineral Resin from San Ber- 
nardino County, Cal.; by J. M. STILLMAN, Ph.B. 
TurovGH the kindness of Mr. B. B. Redding, o of Fran- 
cisco, I have been put in possession of some pee ns of a 
new and interesting mineral said to occur in co uan- 
tity in San Bernardino County, California, ee ex by 
excavations for a tunnel. The pieces in my possession were 
omogeneous masses of from one to five or six E cubic inches 
