the similarity of character there is between some of the gaseous bodies and the galvanic fluids, a general view of those analogies will be found of considerable advantage throughout the most obscure and difficult part of the inquiry.

If a united stream of oxygen and hydrogen gases be lighted, and blown upon bodies that are even difficult of combustion, they will be quickly consumed by the continued action of these gases; and it is also a fact, that when the two galvanic fluids are thrown upon the same class of bodies they will produce similar effects. In the common and regular process of combustion the presence of oxygen is indispensably necessary; but when the bodies to be burnt are placed in a gas that contains no oxygen, or even in an exhausted receiver, they may be consumed by the agency of the galvanic fluids.

When a galvanic battery acts in the most powerful manner, particularly in the display of its chemical energies, there is a singular coincidence of results during its action that is worthy of notice, for a part of the water in the battery is decomposed, and at the same time two galvanic fluids appear to be liberated from the battery, whose character, in many other instances besides those just mentioned, bears a strong resemblance to the two gases obtained from the decomposition of water.

At present we may not be able to comprehend clearly the law by which these newly discovered galvanic combinations are generated; but if we follow the evident changes that water undergoes by its union with different portions of caloric, we may perhaps venture to infer that these galvanic agents are generated during the action of the battery by a principle somewhat similar.

Water in its solid form, or character, of ice, is united comparatively with a small quantity of caloric, when combined with a larger portion of this agent, it obtains the liquid state: but if united to a still greater portion, it assumes the character of steam, and often displays a mechanical force that is as singularly striking as the power of the galvanic fluids. By the application of a greater degree of heat than what is necessary for the changes already stated, the constituent parts of water become separated, and assume the state of two invisible gases, whose peculiarities approximate much nearer the character of the galvanic fluids: for the fact that oxygen and hydrogen gases mixed in proper quantities enter into combustion, when sufficiently influenced by heat or a mechanical force, presents a strong feature of those agents; as it is more than probable, from the velocity with which the galvanic fluids move, that in many instances they produce a high degree of temperature by their mechanical action upon each other, and the bodies that impede their free circulation, which gives rise to their combustible energies.

Although a variety of circumstances already mentioned appear to support the idea that the bases of the galvanic fluids are derived from the liquid in the battery, and partake of an oxygenous and hydrogenous nature; still it is extremely probable that these newly

discovered compounds are formed by a very different union with caloric from that which takes place in the formation of oxygen and hydrogen gases, as we have not the least evidence that the greatest possible attenuation we could obtain by the application of heat to these gases would impart to them any electrical energies.

If we take into consideration the subtile and active nature of caloric, and compare it with the most attenuated gaseous bodies yet known, we shall see the probability that other compounds of this nature may be formed by the action of various chemical and mechanical forces, that must hold a rank between gaseous bodies and caloric; and, according to the established rules of analogy, are likely to be endowed with energies strongly resembling the powers of the galvanic fluids. The idea that a class of highly attenuated compound bodies holds a place between well-known gaseous bodies and caloric, deserves perhaps more attention from its reasonableness, than any direct evidence we at present possess; as we cannot fairly suppose that this agent, which in its active state converts the hardest and closest metals into vapour, and can by its influence change a solid mass of ice into two combustible gases, should lose this transforming power exactly at the point where it gives these bodies this gaseous character, when there is evidently such a wide difference between the comparatively dense nature of these gases and caloric.

If we admit the probable existence of these highly attenuated compounds, no results can be more reasonably expected from their action, than some of the effects we obtain by galvanism; as combinations partaking of a small portion of oxygen and hydrogen, intimately combined with a large quantity of caloric, must partake in a great degree of its active and penetrating nature, while their bases are calculated to produce many similar effects to those which are obtained by the energies of the galvanic fluids. This appears a simple mode of accounting for the production of what are termed the galvanic fluids; and the principle by which they seem to obtain their energies appears consistent with the idea that they are generated by the action of the battery.* When a galvanic combination produces a strong chemical action, these fluids are given out in great abundance, and it is not improbable that they are propelled along the conducting circuit by the high degree of elasticity which every succeeding portion obtains at the point of generation. In some experiments made to show the transfer of acid and alkaline bodies by the galvanic influence, the results obtained seem intimately connected with this part of the inquiry, as they evidently point out two opposite galvanic currents, and support the above opinions.

The experiments were made by using two small gold conical cups; in one was placed a solution of the sulphate of potash, and

* In these remarks we have supposed the galvanic fluids to be produced by a strong chemical action; but when obtained without this violent action, their character approaches much nearer to common electricity, and will be considered with greater propriety under a more general view of the subject.

in the other pure water, and the liquid in the two vessels was united by moistened amianthus ; when the cup in which the saline mixture was put was galvanized positively, and the other cup negatively, the solution in the positive cup was soon found to have acquired a considerable degree of acidity, while the potash of the solution was transferred to the cup that contained the pure water. But when that cup which contained the saline mixture was galvanized negatively, and the other positively, the potash was left, and the acid portion transferred to the other cup, clearly showing, when a solution which contains an acid and an alkali is decomposed by the action of the galvanic fluids, that the positive fluid transfers the alkaline, and the negative fluid the acid, part of the solution.

This transfer of an acid substance through a fluid conducting medium, from the negative to the positive wire, appears the most conclusive fact ever published in favour of two distinct electric or galvanic fluids; as we cannot, on any rational principle, explain this transfer of matter, if we suppose the wire called the negative wire to be deficient in galvanic electricity, and supplied by a current passing from the opposite or positive wire.

The various results attending the heating and melting of steel wire when placed in the galvanic circuit also support the idea of two opposite galvanic currents. These effects most probably arise from the two opposite currents not having room to pass each other freely along the small steel wire; and their action upon each other gives birth to that combustible energy which their constitutional' character is calculated to support. Although we are furnished with such strong evidence that there are two different and opposite galvanic currents in most experiments; yet it must seem rather extraordinary that these fluids should pass each other in contrary directions, when each fluid is generally supposed to have so great an attraction for the opposite kind, as in most instances to produce combustion by the violence and rapidity of their union. These remarks naturally introduce another very interesting question, viz. What evidence have we that the galvanic or electric fluids have such a strong attraction for each other? But as an inquiry into this question is not necessary for my present purpose, I shall defer it until another opportunity. In the investigation of any difficult subject, when we have no clear and positive evidence to direct our conclusions, we must apply to the aid of analogy, and take advantage of the most appropriate facts which the present state of the subject furnish for our consideration. By the rapid union of oxygen and hydrogen gases, we obtain results that resemble most of the combustible effects of galvanism; still we know the two gases show no strong signs of attraction for each other, without the application of an extra portion of heat, or a mechanical force; may we not therefore infer that it is by a similar law that the galvanic fluids unite and produce their combustible effects; for although their con. stitutional nature will allow them to pass each other in a complete galvanic circuit, yet when they rush upon each other from the

opposite wires of a battery, which are the terminating points of a broken circuit, the mechanical action resulting from their contrary forces may induce them to unite with such rapidity as to render manifest all their combustible energies. This principle of action, and the probability that the bases of the galvanic fluids partake of an oxygenous and hydrogenous nature, will enable us to form a tolerably correct idea of the combustible effects of galvanism; but the most perplexing results attending the galvanic phenomena are said to be the invisible transfer of different bodies through various fluid media.

From the view we have taken of the subject there must be at the same time a distinct fluid quitting the end of each wire that proceeds from the battery, when they are placed in an imperfect conducting fluid medium; and to keep up the evident circulation, each fluid must endeavour to gain the wire opposite to the one it has quitted; it is therefore highly probable that the opposing forces of these contrary currents of the galvanic fluids, give rise to their powers of decomposition, rendered so manifest at the end of each conducting wire of a battery.

These general conclusions give us a new hypothetical view of the galvanic phenomena, the truth or correctness of which, will be the best ascertained by its application to explain what are termed the most perplexing results in galvanism.

In attempting to account for the invisible transfer of acid and alkaline matter through various fluid media, and the appearance of oxygen and hydrogen gases at the opposite wires of a battery, when separated by a column of water some feet in length, the correctness of this hypothesis will be put to a tolerably fair trial.

If we consider the characters we have attributed to the galvanic fluids, the invisible transfer of this acid and alkaline matter in opposite directions appears consistent with the view we have taken of the subject; for if the base of the positive fluid partakes of an oxygen nature, this fluid will probably convey to the negative wire, by the influence of affinity, the alkaline part of any saline solution which is decomposed at the positive wire, and deposit the greater portion of this transferred matter at the negative wire, when it enters that metallic part of the circuit.

We have supposed also that the base of the negative fluid may partake of an hydrogenous or alkaline nature, consequently this fluid may by the force of affinity convey the acid portion of any saline solution decomposed at the negative end of the battery, towards the positive wire; and there deposit this acid matter, when it enters the metallic part of the circuit; and this exchanging process most probably goes on, until the alkaline part of the solu tion is collected round the negative wire, and the acid portion of the same compound is collected round the positive wire of the battery. On this principle we may account for the appearance of oxygen and hydrogen gases at the opposite wires of a battery, though separated by several feet of water.

When water is decomposed by the galvanic action, and two distinct gases appear at the opposite wires, although separated by such a body of water, one of these gases must have been transferred in an invisible manner from one wire to the other, or the water must have been decomposed at each wire, and the constituent portions which do not appear at the point of decomposition must have become so far changed and influenced by the fluids from the battery, as to have passed with them through the water in an invisible state. This latter opinion, though rather novel, is agreeable to what has been advanced, and is strongly corroborated by the transfer of other substances, as well as those just mentioned. By keeping in view the preceding illustration of galvanic effects, it will appear that the hydrogen of the water decomposed at the positive end of the battery will be transferred by the positive fluid towards the negative wire, and there liberated: and that the oxygen of that portion of water decomposed at the negative end of the battery will be transferred by the negative fluid to the positive wire, and be there liberated; and ascend through the water in the character of oxygen and hydrogen gases.

These inferences are supported by the fact, that all the bodies collected and liberated round each wire of a battery possess such characteristic properties as are likely to be influenced by the attractive affinity of the galvanic fluids; if we admit that these fluids possess the constituent nature ascribed to them in this communication.*

The positive evidence we have that the most dense bodies can be transformed by the agency of caloric to assume so many characters, naturally suggests the idea, that a great variety of combinations may take place by its union with the constituent parts of water, which are still unknown; and no products are more likely to be among this class than those elastic compounds which, in all probability, form the galvanic fluids; as they seem a link between well known geseous bodies and caloric, by partaking of the constitutional character of the one, and the action and subtle nature of the other. Nor is it improbable but both the electric and galvanic fluids will, at some advanced period of these sciences, be considered merely as a newly discovered class of peculiar gaseous bodies, sufficiently attenuated by various degrees of caloric to give them different electrical energies.

It is not the results mentioned in this paper only that support this mode of reasoning, for the whole series of regular galvanic

* In a small essay I lately published on Electricity, I have endeavoured to shew the probability that the electric fluids excited by the machine consist of a large quantity of caloric intimately united to a small portion of oxygen and nitrogen obtained from the atmosphere by the mechanical action of the cylinder and rubber. Perhaps if the machine was so constructed that the cylinder could be surrounded and worked alternately in different kinds of gas, the electric fluids excited under these circumstances might display a variety in their chemical action that would lead to some interesting results; and it is not extremely improbable, but that the galvanic fluids would also manifest some variety of character, if they were excited by different agents properly calculated for such a purpose,