1822.] Dr. Hare’s improved Deflagrator. 121 
froma beam, were immersed in atrough without partitions con- 
taining an acid liquor and the defiagrator then connected, its 
power was completely destroyed ; a similar result was obtained 
when 50 pairs of Wollaston’s plates were used: the object in 
these experiments was to ascertain whether a battery in which 
the arrangement of metals was similar to that in the deflagrator 
would produce the same result as the common battery, which 
was the case. In most of the experiments, the connexion of the 
poles was occasionally reversed. This circumstance, however, 
made no difference in the results; a feeble spark was obtained 
as before. ‘Every thing tended to countenance the opinion 
that the interposition of the common galvanic battery operated 
simply as an impediment—that it was completely inert in relation 
to the deflagrator, and the deflagrator in relation to 1t—that the 
power of neither would pass through the other, and consequently 
that each was to be regarded, with respect to the other, simply as 
so much interposed matier constituting a conductor more or less 
imperfect.” ‘This was proved by diminishing the number of 
interposed plates ; when there were 20, the power of the deflagrator 
passed freely, but diminished. As the number was made smaller, 
the power increased, and when one pair only remained, there 
was no perceptible impediment to the power of the deflagrator. 
In another letter, Dr. Silliman relates the phenomena of the 
fusion of charcoal; having been excited to a close observation of 
what took place when charcoal was subjected to the power of 
these instruments, by some observations of Dr. Hare.* The 
pieces of charcoal were prepared by igniting mahogany, buried 
beneath white siliceous sand in a crucible; they were about half 
an inch in diameter, and from 1+ inch to 3 inches in length ; 
they were tapered to a pot, and the cylindrical ends placed in 
sockets connected with the flexible leaden tubes which form 
the polar termination of the series. 
“The metallic coils of the deflagrator being immersed, on 
bringing the charcoal points into contact, and then withdrawing 
them a little, the most intense ignition took place; and I was 
surprised to observe that the charcoal point of the positive pole 
instantly shot out in the direction of the longer axis, and thus 
grew rapidly in length; it usually increased from the tenth to 
the eighth of an inch, and in some instances attained nearly one- 
fourth of an inch in length before it broke offand fell. Yester- 
day and to-day, I have carefully repeated these experiments, 
and in no instance has this shoot from the positive pole failed 
toappear. It continues to increase rapidly, as long as the con- 
tigcous points of charcoal are held with such care that they do 
not strike against each other. When they impinge with aslight 
shock, then the projecting shoot or knob breaks off and falls, 
and is instantly succeeded by another. The form of the project- 
* Vol. i. (New Series) p. 333, of Annals of Philosophy. 
