The view now stated of the constitution of matter would seem to involve necessarily the conclusion that matter fills all space, or, at least, all space to which gravitation extends, (including the sun and its system,) for gravitation is a property of matter dependent on a certain force, and it is this force which constitutes the matter. In that view matter is not merely mutually penetrable, but each atom extends, so to say, throughout the whole of the solar system, yet always retaining its own centre of force. This, at first sight, seems to fall in very harmoniously with Massotti's mathematical investigations and reference of the phenomena of electricity, cohesion, gravitation, &c. to one force in matter, and also again with the old adage "matter cannot act where it is not." But it is no part of my intention to enter into such considerations as these, or what the bearings of this hypothesis would be on the theory of light and the supposed ether. My desire has been rather to bring certain facts from electrical conduction and chemical combination to bear strongly upon our views regarding the nature of atoms and matter, and so to assist in distinguishing in natural philosophy our real knowledge-i. e. the knowledge of facts and laws-from that, which, though it has the form of knowledge, may, from its including so much that is mere assumption, be the very reverse.

It is to be regretted that the memoir of the Rev. Mr. Whewell could not be quoted, being long and obscure. His opinions, it is conceived, have been stated fairly, (1796.)

Motives for republishing my Memoirs on Electrical Theory.'

The principal motive, without which the other motives would not have prevailed, is, that having had an interview with the spirit of Franklin expressly to have his advice, it was given decidedly in favour of publication.

There is no door in the temple of science which is so easy of access as that which leads to the department of electricity. The illustrations usually given at a popular lecture may, at the same time, amuse an infant, instruct a student, and yet perplex a profound philosopher. As associated with the phenomena of thunder and lightning, at one time attributed to the bolt of omnipotent Jove, no consequences of scientific research are so awful and sublime: coupled with the magnetic electric telegraph, no other result so miraculous. While vis inertiæ would keep all nature in statu quo, whether at rest, or like our planet in motion with a velocity fifty times as great as that of a cannon ball: while gravitation tends like the clock weight to produce a definite action and, per se, never to act again: electricity, with a protean diversity of power, appears to be the great instrument of all those changes by which the quiescent influence of the properties above mentioned, is modified in the mundane sphere of chemistry and of life.

Every tyro is aware of the wonderful property imparted to electrics by friction-to the tourmaline by heat; and that the same process, on a large scale, will produce sparks, ignition, combustion, deflagration, and destroy animal life by an instantaneous shock. It is notorious that these won

derful powers may all be imparted to a naked pane of glass, while the charge thus imparted is really only two opposite and equal affections, capable of neutralizing each other by due communication. Known also is it, that properties, to a certain extent similar, may be found in a pile of pairs of heterogeneous metals, with the additional power of electrolysis, or, in other words, of resolving chemical compounds into their ingredients, (1376.) It is well known that, by these means, water, long and almost religiously considered as one of the four elements of the universe, can be decomposed into two kinds of air; that the earths and alkalies have been resolved into metals and oxygen; and that there is scarcely any chemical compound consisting of two elements, which may not, when in aqueous solution or in fusion by heat, be directly or indirectly decomposed by electrolysis, as explained in the note to page 384.

These multifarious feats of electricity have caused it to be contemplated as the source of every thing mysterious in nature. It is not surprising, therefore, that those who, through the accessibility of electricity, had become partially acquainted with electrical phenomena, should view it as the source of spiritual manifestations; while those who have a more extensive knowledge of the nature and extent of electrical jurisdiction should perceive at once that the phenomena in question do not fall within its sphere.

After the discovery, by Oersted, of the previously unsuspected reaction between galvanized wire and a magnetic needle, those who had resorted to either one or two fluids to explain electrical phenomena, found themselves completely at fault. Yet the language originated by Franklin has been still employed conventionally. This, though not misleading adepts, introduces confusion in the minds of those who have merely reached the ante-chamber of the electrical department.

Under these circumstances, I deem it expedient to republish the exposition of electrical theory which I first laid before the scientific world in 1848.

I hope that those who endeavour to refer spiritual manifestations or animal magnetism to electricity, in any of its modifications, will study this exposition of my views.

Though, as already stated, there appears to be, for the spirit world, appropriate elements, distinct from those of this mundane world, there is, nevertheless, a correspondence. We mortals can best prepare ourselves to understand the elements of that world by understanding our own. From an idea of our light and our vital air, we may by analogy conceive of theirs as a preliminary to any further knowledge.

The following theory has been submitted to the spirit of Franklin, who fully approved of it, and fully admitted the validity of the reasons assigned by me for substituting this new exposition of electricity for that which goes under his celebrated name.

Objections to the Theories severally of Franklin, Dufay, and Ampere, with an effort to explain Electrical Phenomena, by Statical or Undulatory Polarization.* By Robert Hare, M.D., Emeritus Professor of Chemistry in the University of Pennsylvania.

1. It appears, from the experiments of Wheatstone, that the discharge of a Leyden jar, by means of a copper wire, takes place within a time so small, that were the transfer of a fluid from the positive to the negative surface requisite for its accomplishment, a current having a velocity exceeding two hundred thousand miles in a second would be necessary.

2. The only causes for the velocity of an electric current, according to Franklin, are the repulsion between the particles of the electric fluid of which it has been assumed to consist, and the attraction between those particles and other matter. These forces are alleged to concur in distributing the supposed fluid throughout space, whether otherwise void, or partially occupied by conducting solids or fluids. Hence, when between two or more spaces, surfaces, or conducting masses, there is an unequal distribution of the electric fluid, the equilibrium is restored whenever a communication is opened by means of a sufficiently conducting medium. Agreeably to this view of the subject, there seems to be a resemblance between the supposed effort of the electrical fluid to attain a state of equable diffusion, and that which would exist in the case of a gas confined in adjoining receivers, so as to be more dense within one than within the other; for, however the subtilty of the supposed electric fluid may exceed that of any gas, there seems to be an analogy as respects the processes of diffusion which must prevail. But on opening a communication between cavities in which any aeriform fluid exists, in different degrees of condensation, the density must lessen in one cavity and augment in the other, with a rapidity which must diminish gradually, and become evanescent with the difference of pressure by which it is induced. Far from taking place in an analogous manner, electrical discharges are effected with an extreme suddenness, the whole of the redundancy being discharged at once, in a mode more like the flight of a bullet, projected with infinite velocity, than that of a jet gradually varying in celerity from a maximum to a minimum.

3. So far, in fact, is an electrical discharge from displaying the features which belong to the reaction of a condensed elastic fluid, that agreeably to the observations of our distinguished countryman Henry, the result is more like the vibrations of a spring, which, in striving to regain its normal position, goes beyond it. The first discharge between the surfaces of a Leyden jar is not productive of a perfect equilibrium. The transfer of

According to Farraday's researches and general experience, we have reason to believe that all particles of matter are endowed with one or the other of two species of polarity. This word polarity conveys the idea that two terminations in each particle are respectively endowed with forces which are analogous, but contrary in their nature; so that of any two homogeneous particles, the similar poles repel each other, while the dissimilar attract; likewise, when freely suspended, they take a certain position relatively to each other, and on due proximity, the opposite polar forces, counteracting each other, appear to be extinct. When deranged from this natural state of reciprocal neutralization, their liberated poles react with the particles of adjacent bodies, or those in the surrounding medium. Under these circumstances, any body which may be constituted of the particles thus reacting is said to be polarized, or in a state of polarization.

Statical implies stationary; undulatory, wave-like.

different polarities goes beyond the point of reciprocal neutralization, producing a state, to a small extent, the opposite of that at first existing; and hence a refluent discharge ensues, opposite in direction to the primary one. But even this does not produce an equilibrium, so that a third effort is made. These alternate discharges were detected by means of the magnetism imparted to needles exposed in coils of copper wire.*

4. Supposing one or more rows of electrical particles, forming such a filament of electricity as must occupy the space within a wire of great length, to be made the medium of discharge to a Leyden jar; agreeably to the hypothesis of one fluid, the electrical filament must be attracted at one end of the wire and repelled at the other, as soon as its terminations are brought into due communication with the coatings of the jar. Yet the influence of the oppositely-charged surfaces of the jar cannot be conceived to extend to those portions of the electricity which are remote from the points of contact, until they be reached by a succession of vibrations. Hence, it is inconceivable that every particle in the filament of electric matter can be made at the same time to move, so as to constitute a current having the necessary velocity and volume to transfer, instantaneously, the electricity requisite to constitute a charge. Even the transmission of the impulses, in such an infinitesimal of time, seems to be inconceivable.

5. In reply to these objections, it has been urged by the Franklinians that a conductor being replete with electricity, as soon as this fluid should be removed at one end, it ought to move at the other. This might be true of a fluid if incompressible, but could not hold good were it elastic. A bell wire moves at both ends when pulled only at one; but this would not ensue were a cord of gum-elastic substituted for the wire.

6. But if the flow of one fluid, with the enormous velocity inferred, be difficult to conceive, still more must it be incomprehensible that two fluids can rush with similar celerity, from each surface of the jar, in opposite directions, through the narrow channel afforded by a wire; especially as they are alleged to exercise an intense affinity; so that it is only by a series of decompositions and recompositions that they can pass each other. 7. That agreeably to the theory of Dufay, equivalent portions of the resinous and vitreous fluids must exchange places during an electrical discharge, will appear evident from the following considerations: One surface being redundant with vitreous and deficient commensurately of resinous electricity, and the other redundant with the resinous and deficient of the vitreous fluid, it is inevitable that, to restore the equilibrium, there must be a simultaneous transfer of each redundancy to the surfaces wherein there is a deficiency of it to be supplied. If, after decomposing a large portion of the neutral compound previously existing on the surface of the jar, and transferring the ingredients severally in opposite directions, so as to cause each to exist in excess upon the surface assigned to it, should the redundancies, thus originated, be neutralized by meeting in the discharging rod, neither surface could recover its quota of the electrical ingredient of which it must have been deprived agreeably to the premises.

8. This calls to mind the fact that no evidence has been adduced of the existence of any tertium quid, arising from the union of the supposed electricities, founded on any property displayed by their resulting combination in the neutral state. It must, if it exist, constitute an anomalous

*Communicated to the American Philosophical Society.

matter, destitute of all properties, and of the existence of which we have no evidence, besides that founded on the appearance and disappearance of its alleged ingredients.

9. But however plausibly the discharges consequent to making a conducting communication from one electrified mass or surface to another mass or surface in an opposite state, may be ascribed to accumulations either of one or of two fluids, neither, according to one theory nor the other, is it possible to account satisfactorily for the stationary magnetism with which steel may be endowed, nor the transitory magnetism, or power of dynamic induction, acquired by wires transmitting galvanic discharges. 10. For the most plausible effort which has been made for the purpose of reconciling the phenomena of electro-magnetism with the theory of two fluids, or with that of one fluid so far as these theories are convertible, we are indebted to Ampere.

11. According to the hypothesis advanced by this eminent philosopher, the difference between a magnetized and an electrified body is not attributable to any diversity in the imponderable matter to which their properties are respectively due, but to a difference in the actual state or distribution of that matter. Statical polarity is the consequence of the unequal distribution of the two electric fluids whose existence he assumes; while magnetical polarity is the consequence merely of the motion of those fluids, which, in magnets, are supposed to gyrate in opposite directions about each particle of the mass. These gyrations are conceived to take place only in planes at right angles to the axis of the magnet; so that, in a straight magnet, the planes of the orbits must be parallel to each other.*

12. The aggregate effect of all the minute vortices of the electrical fluids, in any one plane, bounded by the lateral surfaces of the magnet, is equivalent externally to one vortex, since, in either case, every electric particle on that surface will so move as to describe tangents to a circle drawn about the axis of the magnet. When the electrical vortices of the pole of one magnet conflict in their direction with those of another, as when similar magnetic poles are approximated, repulsion ensues; but if the vortices are coincident in direction, as when dissimilar poles are near, attraction takes place. When a current through a galvanized wiret concurs in direction with the magnetic vortices, as above described, attraction ensues; repulsion resulting when it does not so concur. Hence, the magnet, if movable, will strive to assume a position in which its electrical currents will not conflict with those of the wire on one side more than on the other; also the wire, if movable, will strive so to arrange itself so as to produce the same result, which can arrive only when the needle is at right angles to the wire, and its sides consequently equidistant therefrom. 13. Electric currents will produce magnetic vortices, and, reciprocally, magnetic vortices will produce electric currents. Hence the magnetism imparted to iron by galvanic spirals, and the Farradian currents produced by magnetized iron within spirals not galvanized.

14. Ampere's theory has, in a high degree, the usual fault of substitut ing one mystery for another; but, on the other hand, it has, in an equally

The words gyration, vortex, and whirl are considered as synonymous, and used indifferently to avoid monotony.

† I consider a wire as galvanized, when it is made the medium of the discharge from a galvanic battery.