342 Fusion of Plumbage. 
ed, through the remaining coils. As my hopes of success, 
in the actual state of the instrument, were not very san- 
guine, | was the more gratified to find a decided result in 
the very first trial. To avoid repetitions I will generalise 
the results. ‘The best were obtained, when the plumbago 
was connected with the copper, and prepared charcoal with 
the zinc pole. The spark was vivid, and globules of melted 
plumbago could be discerned, even in the midst of the igni- 
tion, forming and formed upon the edges of the focus of 
heat. In this region also, there was a bright scintillation, 
evidently owing to combustion, which went on where air 
had free access, but was prevented by the vapor of carbon, 
which eccupied the highly luminious region of the focus, 
between the poles, and of the direct route between them. 
Just on and beyond the confines of the ignited portion of the 
plumbago, there was formed a belt of a reddish brown 
color, a quarter of an inch or more in diameter, which ap- 
peared to be owing to the iron, remaining from the com- 
bustion of the carbon of that part of the piece, and which, 
being now oxidized to a maximum, assumed the usual co- 
lor of the peroxide of that metal. 
In various trials, the globules were formed very abundant- 
ly on the edge of the focus, and, in several instances, were 
studded around so thickly, as to resemble a string of beads, 
of which the larg: of the size of the smallest shot ; 
others were merely visible to the naked eye, and others 
still were microscopic. No globule ever appeared on the 
point of the plumbago, which had been in the focus of heat, 
bat this point presented a hemispherical excavation, and 
the plumbago there had the appearance of black scorie 
or yoleanic cinders. These were the general appearances 
at the copper pole occupied by the plumbago. 
_ On the zine pole, occupied by the prepared charcoal, 
there were very peculiar results. This pole was, in every 
instance, elongated towards the copper pole, and the black 
matter accumulated there, presented every appearance » 
of fusion, not into globules, but into a fibrous and 4 
striated form, like the half flowing slag, found on the 
upper currents of lava. It was evidently transferred, in the 
state of vapor, from the plumbago of the other pole, and 
had been formed by the carbon taken from the hemispher- 
ical cavity. It was so different from the melted charcoal, 
described in my former communications, that its origin 
