Electric Batteries - by A. Volta
In this article I present my translation of Alessandro (Alexander) Volta's original French paper, which I published as -
Batteries électriques - By A. Volta
Volta's batteries are of a type now known as electrochemical batteries, to distinguish them from the prior class of electrostatic batteries as described by Benjamin Franklin in his letter to Peter Collinson of 1749. The 'Cavallo electrometer' mentioned by Volta can be seen at sparkmuseum.com. The electrophorus which he mentions is a capacitive charge generator. Invented by Johan Carl Wilcke, the electrophorus was improved by, and named by, Alessandro Volta.
Public domain, courtesy Wikimedia.
The illustration below, from Wikipedia, is of a Volta battery on display in the Tempio Voltiano.
I have retained much of the original French punctuation so that the two documents may be more readily compared. I have also retained the somewhat archaic style, and terms such as 'humour', which in this context means any suitable moistening or dampening agent. The archaic term 'motor' or 'electro-motor' referred to any substance which seemed to 'motivate' a flow of electric current.
I do not pretend any fluency in French, and especially not the French of 1800: this is a technical translation. Accordingly, suggestions for improvements from French speakers are most welcome.
As in the French language version, the image below may be seen as a much larger version at the end of the text.
ROYAL SOCIETY of LONDON
FOR THE YEAR MDCCC
XVII. On the Electricity excited by the mere Contact of conducting substances of different kinds. In a letter from Mr. Alexander Volta, F.R.S. Professor of Natural Philosophy in the University of Pavia, to the Rt. Hon. Sir Joseph Banks, Bart. K.B. P.R.S.
Read June 26, l800
Como, Milan. March 20 1800.
After a long silence, for which I will not try to apologize, I am pleased to inform you, Sir, and through yourself the Royal Society, of some striking results which I obtained, in continuing my experiments on the electricity excited by the simple mutual contact of metals of different kinds, also by that of other conductors, also different from one another, whether liquid or containing any humour, from which they obtain their conducting power. The most important of these findings, which applies to almost all the others, is the construction of a device which resembles Leyden jars in its effects, that is to say the jolts one may experience in the arms, &c., and even more resembles weakly charged electric batteries, that, however, acts constantly or whose charge re-establishes itself after each flash; it enjoys, in a word, an unfailing and perpetual capacity, or impulsion, to act on the electric fluid; but also differs from those essentially, by this continual action which is its property, and because instead of consisting, as with bottles and ordinary electric batteries, of one or more insulated strips, it consists of thin layers of those bodies supposed to be the only electrics , bundled with conductors or bodies said to be non-electrics, this new device is formed only from several of these latter assemblies, chosen from the best conductors, and those most separated, following what has always been believed , as to electrical type. Yes, the apparatus of which I shall speak, and which will no doubt surprise you, is nothing but an assembly of a number of good conductors of different species, arranged in a certain manner, 30, 40, 60 pieces, or as required, of copper, silver or best of gold, each applied to a piece of tin, or, which is even better, zinc, and an equal number of layers of water, or some other humour or better conductor than simple water, such as salt water, lye &c. or pieces of cardboard, leather &c. well saturated with these humours; of such layers interposed between each couple or combination of two different metals, such an alternation, and always in the same order, of these three kinds of conductors, that is all that constitutes my new apparatus; which mimics, as I said, the effects of Leyden jars or electric batteries, giving the same jolts as them, which in truth are much less than the actions of those batteries charged to a high level, likewise the strength and the sound of the striking of the spark, the distance over which the discharge can operate , &c. matching only the effect of a battery charged to a very weak degree, yet a battery with a huge capacity; but which also infinitely surpasses the virtue and power of these batteries, in that it does not need, like them, to be charged in advance, by an external electricity, and in that it is capable of giving a jolt every time we make proper contact, however frequent the contacts.
This device, and the one which I am going to build, resembling in its basic form, as I will show, the natural electric organ of the torpedo, the trembling eel, &c. much more than it does the Leyden jar, and known electric batteries, I would wish to call it an artificial electric organ. And truly is that not, like this one, composed entirely of conductive bodies? Is it not also active by itself, without any previous charge, without the aid of any electricity excited by any means known to date, acting constantly and relentlessly, able to give at any time stronger or weaker shocks, depending on the circumstances, shocks which repeat at every contact, and which even if repeated frequently, or continued for a certain time, produce the same numbness of limbs that the torpedo &c. make us feel ?
I will give here a more detailed description of this device, and some others which are analogous, also, of the most remarkable related experiments.
I provided myself with a few dozen small round plaques or discs, of copper, brass, or better silver, an inch in diameter, more or less (for example, coins,) and an equal number of plaques of tin, or, which is much better, zinc, about the same shape and size; I speak of approximation because accuracy is not required, and, in general, the size as well as the shape of the metal parts is arbitrary: we need consider only that they can be conveniently arranged on top of each other in the form of a column. I also prepared a great enough quantity of roundels of cardboard, leather, or some other spongy material, capable of absorbing and retaining a great amount of water, or humour, such as will suffice for successful experiments , so that they were well soaked. These slices or roundels, which I call damp discs, I make a little smaller than the disks or metal plaques so that, interposed between them, the way I describe now, they do not protrude.
Having at hand all the parts in good order, that is to say, the metal discs clean and dry, and the non-metallic ones well soaked with plain water, or, which is much better, of salt water, and then dried slightly, so that the humour does not drip, I did nothing more than to arrange them as convenient, and this arrangement is simple and easy.
I then place horizontally on a table or any base, a metal plaque, for example, one of silver, and on the first I place a second of zinc, on the second I lay a damp disc, then another silver plaque, followed immediately by another of zinc, on which I again place a damp disc. I continue in the same way, pairing a silver plaque with one of zinc, and always in the same sense, that is to say, the silver is always placed below and the zinc on top, or vice versa, depending on how I began, and inserting between each of these couples, a damp disc, I continue, I say, to form, of several of these stages, a column as high as can support itself without collapsing.
But, if it should contain about twenty of these stages or couples of metal, it will be capable, not only of showing signs of electricity by means of Cavallo's electrometer, with the aid of a condenser beyond 10 or 15 degrees, and of charging this condenser by mere contact so as to make it emit a spark, &c. but of giving small shocks to the fingers with which its extremities (the head and foot of the column) have been touched, and more or less frequently, depending on how one repeats the contact. Each of these shocks has a perfect resemblance to that slight shock experienced from a weakly charged Leyden jar, or a (Leyden) battery still more weakly charged, or a torpedo in an exceedingly languid state, which imitates even more the effects of my apparatus, by the series of repeated shocks which it can continually communicate.
To obtain such slight shocks from this apparatus which I have described, and which is still too small for great effects, it is necessary that the fingers, with which the two extremities are to be touched at the same time, should be dipped in water, so that the skin, which otherwise is not a good conductor, may be well moistened. Further, to succeed with more certainty, and receive stronger shocks, a connection must be made, by means of a sufficiently large metallic strip, or a large metallic wire, between the foot of the column (that is to say, the lower piece of metal,) and water contained in a bowl or large cup, in which one, two or three fingers, or the whole hand is to be immersed, while you touch the head or upper extremity (the uppermost, or one of the uppermost plaques of the column) with the clean extremity of another metallic strip held in the other hand, which must be very moist, and must grip a large surface of the strip very tightly.
Proceeding in this way, I can already get a little tingling, or mild shock in one or two finger joints immersed in the water of a bowl, in touching, with the strip in the other hand, a fourth or even third pair of plaques and then touching the fifth, sixth, and step by step the others, until the last set, which is the head of the column: it is curious to experience how the shocks gradually increase in strength. However, this force is such that I am able to receive from such a column, consisting of 20 pairs of plaques (no more,) shocks that affect all the fingers, and affect them quite painfully; provided that they are immersed in the water of the bowl; effects which extend (without pain) to the wrist, and even to the elbow, if the hand is immersed in great part or completely, and can even be felt at the wrist of the other hand.
I suppose always that one has employed all the necessary precautions in the construction of the column, and that each pair or couple of metallic pieces, made from a plaque of silver applied over one of zinc, is in communication with the following couple by a sufficient stratum of moisture, consisting of salt water rather than common water, or by a piece of pasteboard, leather, or any thing of the same kind, well impregnated with this salt water; which disc must not be too small, and its surface must adhere closely to those of the metallic plaques between which it is placed. The exact scope and application of damp discs is very important; ensuring that the metal plaques of each pair do not touch even a little, except where they are in direct contact.
All this goes to show (to put it in passing) that if the contact between the metals at some points is sufficient (all being excellent conductors) to give free passage only to a moderately strong electric current, it is not so for liquids, or for bodies soaked with humour, which are much less perfect conductors, and therefore need ample contact with the metal conductors, and even more between them, so that the electric fluid can pass with relative ease, and is not too delayed in its course, especially when it is driven with very little force, as in our case.
Moreover, the effects of my device (the shocks one feels) are significantly more sensible, as the temperature of the ambient air, or that of the water, or of the damp discs which enter into the composition of the column, also the water in the bowl is warmer, the heat making the water more conductive. But what makes it much better yet, are almost all salts and notably common salt. This is one reason, if not the only reason, why it is advantageous if the water in the bowl, and above all that which is between each pair of metal plaques: the water which is soaked into the cardboard discs, &c. is salt water, as I have already noted.
But all these methods, and all these details, in the end, have limited benefit, and it never will be possible to obtain very strong shocks, so long as the device consists of a single column of only 20 pairs of plaques, though they are of the two best metals for these experiments, to wit, silver and zinc; since, if they were of silver and lead, or of tin, or of copper and tin one would not obtain the half of the effect, unless a much greater number should compensate for the lack of strength of each pair. However, that which actually increases the electrical power of the unit, and may bring it to a level to match, and even surpass, that of the torpedo and electric eel, is the number of plaques arranged in the manner, and with the care, which I have explained. If to the 20 pairs described above, we added 20 or 30 others, arranged in the same order, the shocks which the column can give are accordingly prolonged, (I will describe at some time how we can support it, so that it does not collapse, or, which is better, its separation into two or more columns) will already be much stronger, and will extend in both arms up to the shoulder, especially in the one whose hand is plunged into the water; on which side, the whole arm will remain more or less numb, if, in repeating the contacts frequently, one can repeat these shocks one after another rapidly and unabated. This, in immersing all, or almost all, the hand in the bowl of water; but if it is only a finger dipped in whole or in part, the shocks, concentrated almost entirely in it, will be even more painful, and so excruciating they become unbearable.
It is expected that this column, formed of 40 or 50 pairs of metals, which gives more than mediocre shocks to both arms of a person, could give even more sensible shocks to several, who holding their hands, (sufficiently wet) form an unbroken chain.
Returning to the mechanical construction of my apparatus, which is capable of many variations, I shall describe here, not all the ones which I envisioned and built, either large or small, but only a few of those which are the most curious or useful, which have some real advantage, such as to be of an easier or more expeditious execution, to be more infallible in their effects, or much longer maintainable in good condition.
And to begin with one, which, uniting nearly all of these advantages, differs the most in its appearance, from the column apparatus described above, but has the disadvantage of being a much more bulky apparatus; I present this new device to you, which I shall call a crown of cups, in the attached figure. (Pl. XVII. Fig. 1.)
One disposes, then, a row of several beakers or cups of any material whatsoever, except metal, such as wood, totoiseshell, earthenware, or better of glass (small tumblers or drinking glasses are the most convenient), half filled with pure water, or rather salt water or lye; and they are all made to communicate by forming them into a sort of chain, by means of many metallic arcs, one arm of which, A-a, or only the extremity A, immersed in one of the tumblers, is of copper or brass, or better, of copper plated with silver; and the other, Z, which is immersed in the next tumbler, is of tin, or better of zinc. I observe here, in passing, that lye and other alkaline liquors are preferable, when a metal that will be immersed is tin, salt water is best when it is zinc. The two metals of which each arc consists are soldered together in whatever area is suitable, above the part immersed in the liquid and which must cover a sufficiently large surface: it is suitable for this, that this part is a strip of a square inch, or very little less, the rest of the arc may be narrower as you wish, and even a simple wire. It may also be a third metal, different from those which dip into the liquid of the cups, since the action of the electric fluid, which results from all the contacts of several metals which follow one another in succession, the force with which the fluid is pushed to the end, is absolutely the same, or nearly so, as that which it would have received by the direct contact of the first metal with the last , without any intermediate metals, as I have verified by some direct experiments, of which I shall have occasion to speak elsewhere.
Now, a series of 30, 40, 60 of these cups. enchained in this manner, and stored either in a straight line or a curve, or folded in all manners, form the entirety of this new apparatus, that in its basis, and in essence, is the same as the other column , described above, essentially consisting in the immediate communication of different metals that make each couple, and mediating between one couple and another, namely, through the medium of a wet conductor taking the place of a couple, as with the other apparatus.
It is easily understood that, to produce a shock, it is sufficient to dip a hand into one of the cups, and a finger of the other hand into another cup, far enough away from it so that the shock will be even stronger as these two vases are more distant one from the other, that is to say, there will be a greater number of intermediaries; that consequently, it will be strongest, in touching the first and last of the chain. One also understands how and why the experiments succeed much better, in grasping and squeezing in a well-moistened hand, a broad metal strip (so that the communication here is quite perfect and achieved through a large number of points ,) and touching with this strip the water in the goblet, or rather the inscribed metal arc, while the other hand is plunged into another cup further away, or touch, with a strip similarly gripped, the arc thereof. Finally, one understands, one can even predict the success of a great variety of experiments, which one can execute with this crown of cups apparatus, more easily, and in a manner more obvious and eloquent, so to say, to the eyes, than with the other column apparatus. I shall thus dispense with describing a great many of these easily imagined experiments, and I shall relate only a few that are no less instructive than amusing.
Let three score of these beakers or cups, be arranged and connected with each other by metallic arcs, but fashioned such that, for the first twenty, these arcs shall be turned in the same sense; for example, the arms of silver turned to the left, and the arms of zinc to the right; and for the second twenty in a contrary direction, that is to say, the zinc to the left, and the silver to the right: in the last place, for the third twenty, the silver to the left, as is the case in regard to the first. When everything is thus arranged, immerse one finger in the water of the first tumbler, and with the strip grasped in the other hand, as above directed, touch the first metallic arc (that which joins the first beaker to the second), then the other arc which joins the second and third tumbler, and so on, in succession, until you have touched them all. If the water be very salty and lukewarm, and the skin of the hands well moistened and softened, you will already begin to feel a slight shock in the finger when you have touched the fourth or fifth arc (I have experienced it sometimes very distinctly by touching the third), and by successively proceeding to the sixth and the seventh, &c., the shocks will increase gradually in force up to the twentieth arc, that is to say to the last one of those turned in the same direction; but by proceeding onwards to the 21st, 22nd, 23rd, or 1st, 2nd, 3rd, of the second twenty, in which they are all turned in a contrary direction, the shocks will become at each step weaker, so that by the 36th or 37th, they will be imperceptible, and absolutely nothing at the 40th; beyond which (and commencing with the third twenty, opposed to the second and analogous to the first,) the shocks will be imperceptible to the 44th or 45th arc; but they will begin to become sensible, and to increase gradually, in proportion as you progress to the 60th, where they will have attained the same force as that of the 20th arc.
However, if the 20 middle arcs were turned in the same direction as the previous 20 and the next 20, If all 60 conspire to push the electric fluid in the same direction, we can understand how the effect would be greater at the end, and the shock stronger, and in general we understand how and to what extent, it must be enfeebled, in all cases where a greater or lesser number of these forces, by the opposite orientation of the metals, counteract it.
If the chain is broken in some place, or there is insufficient water in the cups, or a metal arc has been removed, or is separated into two parts, you will receive no shock by dipping a finger in the water of the first vessel and another in the water of the last; but you will have one strong or weak, depending on the circumstances (leaving these fingers immersed) when you restore the broken connection, or when some other person dips two fingers into the cups where the arc is missing, (which fingers will also be subject to a slight shock) or better, that they immerse the same arc which had been removed, or any other, and, in the case of the arc separated into two pieces, as soon as they are brought back into mutual contact, (in such a way as to increase rather than reduce the shock;) finally, in the case of the empty cup, on pouring in the water, it will connect the two metal arms deep in the cup, which were left dry.
When the chain or ring of cups is quite long, and ready to give a strong shock, one will feel it, although much weaker, nevertheless holding two fingers or both hands immersed in one bowl of water of sufficient size, into which the first and the last metal arc are led, provided that one or the other of these hands is covered, preferably both, and one holds them respectively in contact with these same arcs, or near enough in contact, one will experience, I say, a shock at the moment that (the chain being broken somewhere) connection is restored, and the circle completed, in one of the ways of which we have just spoken. Now, we might be surprised that in this circle, the electric current, having free passage through a body of water which is uninterrupted: that water which fills the bowl, leaves the good conductor to flow and continue its course, through the body of the person who has his hands immersed in the same water, thus making a longer path. But the surprise will cease, if we reflect, that the living and warm animal substances, and especially their humours are generally better conductors than water. The body, therefore, of the person who immerses his hands in water, offering an easier passage than this water to the electric current, it must prefer that path, even though somewhat longer. Moreover, as the electric fluid, since it must pass in quantity, through conductors which are not perfect, and namely through wet conductors, tends to expand into a wider channel, or be divided into several, and even take detours, finding in this less resistance than in following a single, but shorter channel; and it is in this case merely a part of the electric current, which, departing from the water takes this new route through the person, and travels from one arm to another; another part, more or less strong, passes through the water in the bowl. That is the reason why the shock which we feel is much weaker than when the electric current is not shared, when the person is the only connection between one arc and another, &c.
From these experiments, one might believe, that when the torpedo wishes to give a shock to the arm of a man, or to animals which touch it, or which approach its body under the water, (which shock is much weaker than that which the fish can give out of the water), it need do nothing but bring together some of the parts of its electric organ, in that place, where, by some gap, the path is interrupted, to remove the gaps from between the columns of which the said organ is formed, or from between its membranes in the form of thin disks, which lie one above the other from the bottom to the top of each column; it has, I suggest, nothing to do but to remove these gaps in one or more places, and to produce there the requisite contact, either by compressing these columns, or by making some moisture to flow in between the pellicles or diaphragms which have been separated, &c. That is what may be, and what I conclude to be in reality, the entire task of the torpedo, in giving a shock; since all the rest, the impulse and movement communicated to the electric fluid, is only a necessary effect of its singular organ, formed, as one sees, of a very numerous set of conductors, which I have every reason to believe are sufficiently different from each other to be also exciters of the electric fluid by their mutual contacts; and to suppose them arranged in a manner convenient for impelling that fluid with a sufficient force from top to bottom, or from bottom to top, and for establishing a current capable of producing the shock, &c. as soon as, and each time that, all the necessary contacts and connections take place.
But now let us leave the torpedo, and its natural electric organ, and return to the artificial electric organ of my invention, and particularly that which mimics the former in its form (for that of cups departs from it in this regard ,) let us return to my first columnar apparatus. I shall have something more to report of the construction of the said cups apparatus, or crown of cups, for example that it is good for the first and last cups to be large enough to be able to immerse, on occasion, an entire hand, &c. ; but it would take too long to go into all those details.
As for the column apparatus, I looked for ways to lengthen it greatly, increasing the number of metal plates without it crumbling ; for ways of making this instrument convenient and portable, and, above all, durable ; and I have found, among others, the following, which I place before your eyes, by means of the attached figures. (Pl XVII. Fig. 2,3,4.)
In Fig. 2, m m m m, indicate supports or rods, three, four, or more in number, which rise from the bottom of the column, and contain, as in a cage, the plaques or discs stacked on top of each other, in such numbers, and to the desired height, and thus prevent their falling. The rods can be glass, wood, or metal, only in the latter case, they must be kept from immediate contact with the plaques; what one can do, is cover each of these metal rods with a tube of glass, or interpose, between them and the column, a few strips of oilcloth, oiled paper, or even plain paper, or at least any other body, that is an obstructor or bad conductor: wood or paper will suffice for our purpose, provided only that they are not extremely damp or wet.
But the best expedient, when one wishes to form an apparatus from a very large number of plaques, beyond, for example, 60, 80, 100, is to divide the column in two, or more, as we see in Figures 3 and 4 (Pl. XVII) where the parts all have their respective positions and connections, as if it were a single column. One can in effect regard Fig. 4e, as well as 3e, as a folded column.
In all these figures, the various metal plaques are designated by the letters A and Z (which are the initial letters of argent [silver] and zinc;) and damp discs (cardboard, leather &c) interposed between every metal couple, shown by a black layer. The dotted lines mark the union of one metal with another, in each pair, making their mutual contact by any number of points; no matter how, or being soldered together, which is good in many respects. cc, cc, CC, are metal strips, which connect one column or column section, to the other, and b, b, b, b, b, are the bowls of water, in communication with the feet or extremities of the columns.
An apparatus thus mounted is quite convenient, not bulky, and one might make it even more safe and portable, with a few casings or tubes, in which one may hold and support each column. It is a pity only that it does not last a long time in good condition; the damp discs drying out in a day or two, to the point that they must be moistened again; what can be done, however, without dismantling the entire apparatus, is to immerse the entire columns in water, and (their having been removed some time after) wiping the exterior with a cloth, or some other thing, the best we can.
The best way to make it as durable an instrument as one could wish would be to enclose and retain water interposed between each pair of metals, and set these plaques in their places, enveloping the entire column with wax or pitch, but the thing is a bit difficult to execute, and requires a lot of patience. But I have succeeded and I have formed in this way, two cylinders of 20 metal couples, which serve me well enough still, after a few weeks, and will, I hope, after some months.
One has the convenience of being able to use these cylinders in experiments, not only standing, but inclined, or lying, as one wishes, and even immersed in water, with only the head exposed: they are still able to give jolts when fully immersed, if they contain a very large number of plaques, or if several of these cylinders were joined together, and there were some interruption, which one could remove at will, &c. with which, these cylinders imitate the electric eel well enough ; to better resemble which, on the outside also, they could be joined together by flexible metal wires, or coiled springs, and be covered throughout their length with a skin, and terminate in a head and a tail, well configured, &c.
The effects sensible to our bodies that a unit consisting of 40 or 50 pairs of plates produces, (and even fewer, if any metal is silver or copper, the other zinc,) are not simply reducible to shocks: the current of the electric fluid, driven and urged by such a number and species of different conductors, silver, zinc and water, arranged alternately as described excites not only contractions and spasms in the muscles. The more or less violent convulsions in the members that it traverses in its course, but it irritates also the organs of taste, sight, hearing, and touch, and presents to each its own kind of sensation.
And, firstly, on the sense of touch; if, by means of an ample contact of the hand (well moistened) with a metal strip, or better, by immersing the hand deep into the bowl of water, I establish on one side a good connection with one end of my electro-motor unit (one must give new names to the new instruments, not only according to the form, but also to the effects, or the principle upon which they depend ,) and the other side I apply to the forehead, eyelid, the nose, also moistened, or any other part of the body where the skin is very delicate ; I apply, I say. with a little pressure, one of those delicate parts, well moistened, against the tip of a wire that is properly connected with the other end of the said apparatus, I feel, in the moment that the circle of conductors is thus completed, at the location of the skin contact, and a little beyond, a jolt and bite, which pass quickly, and which repeat as often as one interrupts and restores the circle, so that if these alternations are frequent, they cause me a trembling, and a strong disagreeable tingling. But if all communications continue without these alternations, without the slightest interruption of the circle, I sometimes do not feel anything for several moments, except for those sensations which commenced at the part to which the wire was applied, another sensation, a sharp pain (without shaking) specifically limited to the points of contact, burning, not only continuing, but ever increasing, to the point of becoming unbearable in little time, and which does not cease except by interrupting the circle.
What clearer proof of the continuation of the electric current for the whole time that the connections continue of the conductors which form the circle? And only by interrupting it, such a current is suspended? This endless circulation of electric fluid (this perpetual motion) may seem paradoxical, may not be explicable, but it is none the less true and real, and one may touch it, so to speak, with the hands. Another obvious proof can also be learned, that, in these kinds of experiments, we often feel, when the circle is interrupted suddenly, a sting, a jolt, according to circumstances, as in the moment that it is completed; with the only difference that these sensations caused by a kind of reflux of the electric fluid, or the shock that springs from the sudden suspension of the current is weakest. But I do not need, and this is not the place to argue the evidence of such an endless circulation of electric fluid, in a circle of conductors when there are those which, being of different species , perform by their mutual contact, the office of exciters or motors: this proposition, which I have advanced from my initial research and discoveries on the subject of Galvanism, and always sustained, with the support of new facts and experiments, will, I hope, have no more opponents.
Returning to the sensation of pain we felt in the experiments described above, I must add that if the pain is quite sharp in parts covered by the skin, it is much more so where the skin has been removed, in wounds, for example, and recent sores. If by chance there is a small cut, or scratch, on the finger which I dip into the water communicating with one end of the electro-motor device, then I feel such a sharp pain and stinging if, on establishing the proper connection with the other end I make the circle complete, that I must soon desist from the experiment, that is to say, remove the finger, or otherwise interrupt this circle. I will say moreover, that I cannot even resist beyond a few seconds, when the part of the unit which I bring into play, or the entire apparatus, comprises only 20 metal couples, or thereabout.
One thing I have yet to remark is that all these tingling sensations and pain are stronger and more acute, other things being equal, when the body part that must receive them is on the side where the electricity is negative, that is to say, so placed in the circle of conductors that the electric fluid traversing this circle, is not directed against the sensitive part, it does not advance to it and enter from without to within, but its direction is from within outwards, in a word, that it comes: as against what should be found, from the two metals used as couples in the constructed apparatus, depending on which one gives fluid to the other. However, I had already determined that property for all metals, by other experiments, published a long time ago, in consequence of my first memoirs on the subject of Galvanism. I will not say anything else here, except that everything is fully confirmed by experiments equally, and some more, demonstrative and striking, which occupy me at present.
Compared to the sense of taste, I had already discovered and published in those early memoirs, where I saw myself obliged to combat the so-called animal electricity of Galvani, and declare it an extrinsic electricity, driven by the mutual contact of metals of different species, I had, I say, discovered as a result of this power which I attributed to the metals, that these two pieces of different metals, and especially a silver and zinc, properly applied, excite on the tip of the tongue, very marked taste sensations; that the taste was decidedly acid, if the tip of the tongue is turned to the zinc, the electric current will go against it, and will enter, and another taste will be sensed, less strong, but more unpleasant, pungent, and tending to the alkaline, will be felt, if (the positions of the metals being reversed) the electric current leaves the tip of the tongue; that these sensations, moreover, will continue and will increment for several seconds, if the mutual contact of the two metals is sustained and the circle of conductors is nowhere interrupted. But when I have said here, that the same phenomena will arrive punctually, when put to the test, if instead of a single pair of these metal pieces, an assembly of several, arranged as required; and that the named sensations of taste, whether acidic or alkaline, increase, but slightly, with the number of couples, I will have said almost all. It only remains for me to add, that if the apparatus which one brings into play for these experiments on the tongue, is made of a fairly large number of metal couples of this kind, if, for example, it contains 30, 40 or more, the tongue not only feels the sensation of taste as just said, but also, something of a blow, that strikes at the moment that one completes the circle, and that causes a more or less painful, but passing, sting, followed a few moments later, by the lasting sensation of taste. This blow will also produce a convulsion, or trembling, of a part, or all of the tongue, when the apparatus, consisting of a larger number of pairs of said metals, is more active and provides good conductive paths, and the electric current that it excites can go anywhere, with great freedom.
I often return to, and I insist on, this last condition, because it is essential for all experiments where it is desired to obtain good effects on our body, or jolts in the limbs, or sensations in the sense organs. It is therefore necessary that non-metallic conductors entering into the circle, are such good conductors as is possible, well soaked (if they are not themselves liquid) with water, or any other fluid more conductive than pure water, and ensure, in addition to this, that the well dampened surfaces, by which they communicate with metallic conductors, and especially between them, are quite large. The connection should only be shrunk, or reduced to a small number of contact points, where you wish to concentrate the electric action on a more sensitive part of the body, on some sensory nerves, &c. as I have already pointed out, concerning experiments in touch, namely, experiments by which severe pain is excited in different parts. So the best way I have found to produce in the tongue all the sensations described, is, to apply its tip against the pointed end (which is not too much so) of a metal rod that I make in proper communication, as in other experiments, at one end of my apparatus, and establish a good connection with the hand, or, which is better, with both hands together, at the other end. This application of the tip of the tongue to the tip of the metal stick can, moreover, already exist when making the other connection to complete the circle, (when one puts a hand into the water in the bowl) or to do so after establishing this connection, while the hand is immersed and, in the latter case, I think I feel the sting and shock in the tongue, just a little before the true contact. Yes, it always appears to me, especially if I advance the tip of the tongue little by little, that when it has arrived at a very small distance from the metal, the electric fluid, (I would rather say the spark ,) leaps to strike across this interval.
With regard to the sense of sight, which I had also found to be affected by the weak current of the electric fluid, proceeding from the mutual contact of two different metals, in general, and in particular a piece of silver with one of zinc, I ought to expect that the sensation of light excited by my new apparatus would be stronger, in measure as it contained a greater number of pieces of these metals, each pair of which, arranged properly, adds a degree of power to the said electric current, as all other experiments demonstrate, and notably those with the electrometer, with the aid of the condenser, that I have just indicated, and which I will describe elsewhere. But I was surprised to find that with 10, 20, 30 pairs or more, the flash produced appeared not long and extended, or much brighter, than with one couple. It is true, however, that this weak and transient sensation of light, is excited by such an apparatus more readily, and in many ways. In order to succeed with a single pair of metals, there are almost none but the following ways; namely, either that one of the pieces of metal is applied to the bulb of the eye or to the well moistened paper, and that it is made to touch the other metal applied to the other eye, or held in the mouth, which gives the most beautiful flash; alternatively if one grips the second piece of metal, with a well moistened hand, and then one brings it into contact with the first; or else, the two strips are applied to parts of the inside of the mouth, making them also communicate. But, with an apparatus of 20, 30 couples, &c. one produces the same flash, using the tip of a metal strip or rod, which is in communication with one of the extremities of the apparatus, while a hand is conveniently communicating with the other end; on applying, I say, or by bringing into contact with the blade, not only the eye, or any part whatsoever of the mouth, but the forehead, nose, cheeks, lips, chin, even up to the throat ; in a word, all parts and points of the face, which need only be moistened, before bringing into contact with the metal strip. Moreover, the form, such as the strength, of the passing light which one perceives, varies a little, on varying the locations to which one applies the action of the electric current, if it is on the front, for example, this light is moderately strong, and appears as a bright circle, in which shape it also presents itself in several other trials.
But the most curious of all these experiences, is to keep the metal blade clamped between the lips and in contact with the tip of the tongue, as, when one completes the circle in a suitable way, it excites both, if the apparatus is sufficiently large, in good order, and the electric current strong enough and flowing well, there is a sensation of light in the eyes, a convulsion in the lips, and even in the tongue, a painful sting on its tip, followed finally by the sensation of taste.
I have nothing more to say except a word on the hearing. The sense that I had vainly sought to excite with only two metal strips, although the most active among all the drivers of electricity, namely, silver, or gold, and the other of zinc, I finally managed to affect with my new apparatus, consisting of 30 or 40 pairs of these metals. I had introduced beforehand in both ears, two kinds of metal probes or rods, with rounded ends, and I made immediate contact with them at both ends of the device. At the time that the circle had been thus completed, I received a jolt in the head and a few moments later (the connections continuing without interruption,) I started to sense a sound, or rather noise in the ears, which I cannot well define; it was a kind of cracking shock, or bubbling, as if some pate or viscous substance were boiling. The noise continued unabated, and without an increase, the whole time that the circle was complete, &c. The unpleasant sensation, and that which I feared to be dangerous, the shock in the brain, has ensured that I have not repeated this experiment many times.
There remains the sense of smell, which I have tested so far in vain, with my apparatus. The electric fluid, which, set to flow in a full circle of conductors produces in the limbs and parts of living bodies that take part in this circle, effects corresponding to their excitability, stimulates particularly the nerves or organs of touch , taste, sight, and hearing, and excites some sensations specific to each of these senses, as we have found, and produces, in the nose, but a more or less painful tingling, and some more or less widespread jolts, according as the said current is stronger or weaker. And how is it, that it excites no sensation of smell, whatever is done, as it appears, to stimulate the nerves of that sense? We cannot say that the electric fluid, by itself, is not capable of producing odoriferous sensations; since when it is spreading in the air, as filaments, &c. in the ordinary experiences of electrical machines, it carries to the nose a very strong smell, resembling that of phosphorus. I would say further, with more resemblance, and on a basis of analogy with other odoriferous materials, it need only spread in the air, to excite smell, that it needs, as other scents, the vehicle of air to affect this sense in its own way to give rise to sensations of smell. However, in the experiments in question, that is to say, the electric current in a circle of contiguous conductors, and without the least interruption, it absolutely cannot occur.
All the facts that I have reported in this long script regarding the action that the electric fluid, excited and driven by my apparatus, exerts on the different parts of our body that the current invades and traverses; action which, besides, is not momentary, but sustained and durable for the whole time that, the connections not being interrupted, the current follows its path ; action, finally, whose effects vary according to the different excitability of these parts, as one saw, all these facts, already numerous enough, and others that one may yet discover, multiplying and varying the experiences of this kind, will open a large enough field of speculations and views, not only curious, but interesting especially to medicine. That will be enough to occupy the anatomist, physiologist, and the practitioner.
One understands, from the anatomical study that was made, that the electric organ of the torpedo, and electric eel, consists of several membranous columns, filled from one end to the other with large numbers of laminates or films, in the form of very thin discs, lying one above the other, or supported at very small intervals, in which flow, as it appears, some humour. But one cannot suppose that any of these laminates can insulate, as do glass, resins, silk, &c. and still less that they can be electrified by friction, or be capable of being charged in the manner of Franklins' small tableaux, or small electrophores: nor even whether they are bad enough conductors to serve as a good and durable capacitor, as imagined by Mr. Nicholson. The hypothesis of this learned and laborious physicist, by which he makes of each pair of these films, which he would wish to compare to foils of talc, many small electrophores or capacitors, is, indeed, very ingenious ; it is perhaps what one thought best to explain the phenomena of the torpedo, holding to the principles and laws known hitherto about electricity. But it follows that the mechanism by which such ought to operate, for each jolt that fish would wish to give: the respective separation of the plaques, of all or many of these electrophores or capacitors; ought, I say, operate all these separations at once, and establish, on the one hand, a communication between all of the more electrified plaques, and, on the other hand, a communication with all those less electrified, as Mr. Nicholson would have it, apart from this very complicated mechanism seeming too difficult, and unnatural; apart also from the assumption of an electric charge, originally imprinted, and so durable in these films performing the office of electrophores, is fact-free, such a hypothesis falls entirely, as these films of the torpedo organ are not, and could not be, in any way insulators, or susceptible to a real electric charge, much less able to retain it. Any animal substance, as long as it is fresh, surrounded by humours and more or less succulent itself is a fairly good conductor: I say more; although not nearly as obstructive as the resins, or talc to which Mr. Nicholson seeks to compare the films in question, there are none, as I am assured, of living or fresh animal substances, which are not better conductors than water, excepting only fat and some oily humours. But none of these humours, nor fat, especially not semi-fluid, nor fluid entirely, as it is in live animals, may receive an electrical charge, in the manner of insulating laminates, and retain it; indeed , one does not find, that the platelets and humours of the torpedo's organ are greasy or oily. Thus, this body, consisting solely of conductive substances can be compared, neither to the electrophorus or capacitor, nor the Leyden jar nor any electrostatic machine however excited whether by friction, or by some other means capable of electrifying an insulating body, as one has always believed, until my discoveries, the only natural electrics.
To what electricity then, or to what instrument ought the organ of the torpedo or electric eel, &c. to be compared? To that which I have constructed according to the new principle of electricity, discovered by me some years ago, and which my successive experiments, particularly those with which I am at present engaged, have so well confirmed, viz. that conductors are also, in certain cases, exciters of electricity in the case of the mutual contact of those of different kinds, &c. in that apparatus which I have named the artificial electric organ, and which being functionally the same as the natural organ of the torpedo, resembles it also in its form, as I have advanced.
Electric Batteries - By A. Volta
By Patrick Lockerby | June 17th 2013 08:17 PM | Print | E-mail