186 Experiments on Anthracite, Plumbago, sc. 
of them were translucent, shining, and of a light greenish- 
yellow, others were dark coloured; and some of them were 
dull externally. The dark globules, as well as the surface of 
the mass of Plumbago exposed to the flame, was attracted by 
the magnet ; some of the light coloured ones were affected 
by the magnet, but only at the point where they had been 
attached to their support, owing to particles of the support 
adhering to them. During the combustion of the Plumbago, 
there were occasionally, scintillations; the heated surface of 
the mass was brownish. 
A large globule of the lightest colour and magnetic only at 
one point, melted with ease when the compound flux was 
used; 1t formed a transparent mass when hot, and opaque 
and milky when cold. ‘The black ones with the same flux 
were also fused; they were brownish when hot, and greenish 
when cold. They were aeted upon with great difficulty by 
caustic potash, and by carbonate of soda. 
The analysis of this Plumbago gave 
@arbon, - ~- - oS =I} = - . - - 61.27 
Water, = = = = = i Se ie - - - - 5.33 
Silex, - - 10.10 
Residue by incineratton, Alumine, - 3.20 
. eolour of a dirty yel- > 33.4 consisting of < Oxide of iron and 2 20 00 
Towish-red, manganese, 5 
& Loss, 10 
100.00 
Experiment 5th. A specimen of Plumbago remarkably 
pure, from near Bustletown, Penn. was tried with the blow- 
pipe. The globules were formed with difficulty, probably 
owing to its foliated texture, the fused parts spreading over 
the surface. The colour in places was white and translucent, 
in others so dark as to be almost black. | 
With the flux before mentioned, the fused matter was re- 
duced to a transparent glass. 
The analysis of this Plumbago gave 
comes St) Se i ee ye rue - 9540 
ater. - - - - - - - - - - - 0.60 
; Silex, Lees 2.60 
Besidue by incineration eee Oxides of iron and ? 
colour light brick red, ; 5.0 consisting ofy  anganese, 1.40 
Loss, 1.00 
1o9.ne 
