482 M. Th. Sheerer on tnx )0 'Norwegian 
on the identity of electricity from different sources, and with 
those of Fusinieri on the statical electrical discharge, it would, 
follow as a corollary that every disturbance of electrical equi- 
librium is inseparably connected with an equivalent disturb- 
ance of the molecules of matter. In the remarks of Professor 
Schoenbein to which I have alluded, he says that my experi- 
ments seem to prove the transmission of the current from one 
electrode to the other to be effected only by chemical action. In 
Exp. 5, I employed the diminution of oxygen as a measure 
of the quantity detached, conceiving that at the intense heat 
which is produced not a particle of zinc would escape oxidation, 
and without concluding that chemical action was absolutely es- 
sential to the existence of the voltaic arc. I must at the same 
time state that the passage of the current is, as proved in these 
experiments, materially modified by the nature of the elastic 
medium through which it passes, and is greatly aided when 
such medium is capable of uniting chemically with the elec- 
trodes. In pure dry hydrogen, I have never yet been able to 
maintain a continuous arc, except with charcoal, which forms 
carburetted hydrogen ; and Davy in reference to his experi- 
ment of burning charcoal in vacuo states, that a gas was formed 
which detonated with oxygen ; the probability is that some 
slight portion of air obtained access, and thus carbonic oxide 
was formed. On the peculiar relation between the electrodes 
and the elastic intermedium, I feel at present unable to give a 
clear opinion ; the subject is peculiarly difficult; I will content 
myself with stating my present notion to be, that the voltaic 
arc bears a similar relation to common flame, to that which 
electrolysis bears to ordinary chemical action. 
4, Hare Court, Temple, May 7, 1840. 
LXXIII. On two Norwegian Cohalt Ores from the Skutteru- 
der Mine. By Th. Scheerer.^^ 
TN the cobalt mines of Modum in Norway (near Christiania) 
are found, besides the common cobalt glance, two other 
distinct cobalt minerals, which differ in their external cha- 
racters from the usual ore. The following are the descrip- 
tions of these minerals : — 
First kind. It occurs massive as well as crystallized, has 
the lustre of arsenical iron, and exactly the same crystalline 
form, even the characteristic brachy diagonal strije. In 
hardness likewise, and also its spec. grav. = 6*23, it does not 
differ much from that mineral. It is shown by the blowpipe, 
* An extract, communicated by the Author, from the original article 
published in Poggendorflf’s Annalen^ vol. xlii. p. 546. 
