VI. Extract from a Memoir on a Peculiar Connexion 
which exists between the Magnetism evolved by a 
Single Galvanic Combination, and the relative Mag- 
nitude of the Opposing Surfaces of that Combination. 
By FRANCIS GYBBON SPILSBURY. 
[Read Nov. 25, 1822.] 
Anxious to repeat some of the experiments, detailed by 
Professor Cumming in the two Papers published on this subject in 
the Society’s Transactions, (Vol. I.) we proceeded to construct an in- 
strument similar to the galvanoscope* there described, though upon 
* The term galvanoscope appears objectionable, as implying that magnetism may be 
made a measure of galvanism; a supposition unsupported by facts. The galvanic intensity 
of any combination has no relation to the magnetic. In a series of these combinations, 
magnetism is scarcely to be detected, yet is the galvanism intense. In a single combination 
composed of two unconnected plates, a quantity of magnetism is evolved, sufficient to fulfil 
all the phenomena of a powerful magnet; and it is on the first instant of immersion that 
this is most intense. On the opposite hand, galvanism is scarcely to be detected in such 
a combination, and not at alt until the plates have been immersed some minutes. It has 
been indeed alleged that the cause of this seeming difference between a single and com- 
pound combination arises from the non-conductibility of a liquid to magnetism; yet we 
have discovered a combination composed of two plates only, from which galvanism is evolved, 
without magnetism. If a slice of medullary matter, and one of coagulated arterial blood, 
be placed on each other, and platina wires proceeding from each of these be immersed in 
dilute sulphuric acid, the wires will quickly give out gas; which will not cease, until the 
arterial blood is converted on its surface next the medullary matter into venous. By ex- 
posure to air the blood will become again oxygenated, and upon applying it again to the 
medullary matter, galvanism will again become apparent by the decomposition of the dilute 
acid. But, neither oxygenated nor disoxygenated, can any effect be perceived by connect- 
ing this apparatus with the galvanoscope. 
