Observations on the Debate regarding the true nature of Electricity, by Mr A Worley
Sir,
I have recently read with great interest the latest volume of your remarkable journal. As I am sure
most of your readers are aware, the topic that adorned the pages of the last issue was that of the
nature of electricity. There has been much furore surrounding this matter and it is indeed now quite
a controversial debate, so aptly demonstrated by the contradictory theories conceived by your
esteemed contributors. As a result I fear we, the readers, have been divided. If I may be so bold as to
say, it is my wish to share with you my humble opinions on the subject in an attempt to provide a
little clarification. I must confess I felt particularly compelled to contribute to your journal after
reading Mr Humphry Davy’s Bakerian lecture entitled “On some chemical Agencies of Electricity”.
Although I must congratulate Mr Davy on such an outstanding memoir on the chemical theory of
electricity, I feel obliged to alert you to a conflicting memoir that has come to my attention, which
has quite clearly been overlooked.
Before I begin it must be known that I am but an amateur in the field of philosophy and advancing
theories of science. As a man of medicine much of my time is consumed by the rigors of practice. I
do however find nothing more delightful than indulging in philosophical publications such as this
when time allows. As such, I have been an avid subscriber of your journal for many years welcoming
the chance to broaden my philosophical horizons. Anyhow, back to the matter in hand. As previously
mentioned, my main motivation for writing this letter is to enlighten yourself and your readers
about a marvellous unpublished paper on the subject of the nature of electricity. The paper, entitled
“Traité élémentaire sur la Fluide électro-galvanique”, was written by a Swiss philosopher named
Jean André de Luc just one year ago. I stumbled upon this masterpiece purely by chance, whilst
carrying out research at the British Library. I gather it was deposited there by M. de Luc himself after
it failed to capture the attention of the scientific authorities to which he presented it. I must
proclaim after reading the paper for myself, the failure to notice its significance was a massive
injustice for it provides a valuable insight into the characteristics of electricity.
As your readers already know, Mr Davy regards that the production of an electric current results
from chemical action. In his own words: “Thus the Voltaic pile of 20 pairs of plates of copper and zinc
exhibits no permanent electromotive power when the connecting fluid is water free from air; for this
substance does not readily undergo chemical change, and the equilibrium seems to be capable of
being permanently restored through it”.I That is to say that the chemical decomposition of the
interposed fluid is a necessary for an electric current to occur. In the case when water is the
interposed fluid, an electric current cannot be produced because water cannot easily be
decomposed. Another contributor to your journal, William Hyde Wollaston, takes a similar position
in his critique “Experiments on the chemical Production and Agency of Electricity”. He deems it to be
true that chemical reactions are likely to be the cause of electricity rather than its consequence. I
must confess after reading M. de Luc’s paper that I find both of these views profoundly perplexing.
After learning of his findings I was keen to replicate the experiments mentioned in M. de Luc’s
paper, to validate in my own mind the existence of the observations about which I had read. I shall
now describe to you in detail the way in which I performed the experiment M. de Luc calls his
I
On some chemical Agencies of Electricity, Humphrey Davy, 1807
“dissection of the galvanic pile”. The preparation is as follows. The pile must be divided into three
distinct sections corresponding to what can be regarded as the three elements of the pile. These
elements are the two metal plates (in this case zinc and silver) and a cloth that has been saturated
with a fluid (muriate of soda). These distinct sections (which are illustrated below) are kept separate
from each other, or “dissected” by small wire stands that are placed between different pairs of
elements. The result of this dissection is that the action of the pile is confined to one part only and
so it can be more easily determined what effects are produced and from which section of the pile
they originate. The first dissection is placed between the zinc and the silver plates; the second,
between the silver plate and the wet cloth; and the third between the zinc plate and the wet cloth.
When the piles are installed in these three ways, a delicate electrometer is attached to each
extremity.II I have sketched some diagrams to illustrate each dissection, which are included below.
The following diagram shows the elements that make up the pile, in its continuous form.
Silver
plate
Wet cloth
Zinc
plate
Sp
Wc
Zp
Sp
Wc
Zp
Continuous Pile
The first experiment I undertook was upon the pile in which the wire was placed between the two
metals. The diagram below represents the way in which the continuous pile is dissected to achieve
this arrangement.
Wire stand
First dissection
This experiment is similar to the first experiment conducted by Wollaston that is reviewed in his
report, the main difference of course being the dissection between the two metallic plates. I will
now recount to you my observations. Shocks were produced, as indicated by the electrometer, and
it was apparent from the changing colour of a solution of litmus that chemical action had taken
II
Traité élémentaire sur la Fluide électro-galvanique, Jean André de Luc, 1806
place. Correspondingly the zinc plates showed signs of oxidation. For the most part, this pile, with its
metallic plates separated, acts in the same manner as if the parts were continuous, just like
Wollaston’s pile. However the effect is seemingly a lot less powerful.
I then examined the action of the pile when dissected according to the second arrangement, where
the metals were placed together and the wet cloth in contact with the zinc; the silver plate and the
wet cloth being separated from each other by the wire strands. The following diagram demonstrates
the way in which the continuous pile has been separated to form this arrangement.
Second Dissection
I found this dissection to be by far the most interesting. Shocks were produced but no
decomposition took place. That is to say, the electrical effects occurred whilst the chemical effects
were suspended. It is clear to me, just as it was to de Luc, that since the electrical effects continue
independently of the chemical effects, the electrical and chemical effects must originate from
different causes.
I then followed the same practice on the pile with the third dissection. To be precise, the pile was
divided such that the two metals were contiguous to each other and the wet cloth in contact with
the silver plate. The diagram below illustrates the position of the elements that make up this
arrangement.
Third Dissection
In this instance no effects were observed, either electrical or chemical.
I shall now examine the different properties of each pile. The action that took place in the pile
dissected in the first manner was both electrical and chemical. Thus, as previously mentioned, this
system can be regarded as comparable to the pile in the continuous state; for here there are two
metals, either in contact (as in the continuous pile), or connected by wire frames (as in the dissected
pile), that give rise to the electrical effects. With regards to the chemical effects, present are two
metals in which there is a wet cloth interposed. The action that occurred in the pile dissected in the
second manner was restricted to electrical alone. Here the two metals are in contact and thus
produce a current. There is no chemical action because they have no fluid between them. Finally,
there were no effects produced by the pile dissected in the third manner. We have no electrical
effects because on either side of the zinc plate was present two metals with the same electrical
relation (the copper plate on one and the wire frame on the other). As a result, their effects
counteract each other. We have no chemical effects for the same reason as in the previous case;
there was no wet cloth between the two metals.
These experiments are, in my opinion, of great importance to the debate on the nature of electricity
because they demonstrate a distinction between the two modes of action of the pile. Quite clearly,
the electrical effects of the system arise simply due to the combination of the two metals when each
pair is separated by a non metallic conductor. On the contrary, the chemical effects require an
interposed fluid between to be present between them. The existence of these two distinct
properties, I believe, is proved by the different effects produced by the pile in its three states of
dissection. After repeating de Luc’s experiments and witnessing for myself these effects, I have to
disagree with Davy’s premise that an electric current results from chemical action. This statement
clearly cannot hold true, since an electric current existed separately from chemical action in the case
of the second dissection. Quite simply, electrical effects do not arise from chemical action.
With that, all that is left for me to say is that I hope I have provided your readers with a great deal to
ponder and I pray that my insights be of some use in their pursuit of the truth.
I shall remain, Sir,
Yours with greatest respect,
Mr A Worley