1779. This sagacious investigator adverts to the fact, that after each atom in a mass of metallic potassium has combined with an atom of oxygen and an atom of water, forming thus a hydrated oxide—caustic potash—the resulting aggregate occupies much less space than its metallic ingredient previously occupied; so that, taking equal bulks of the hydrate and of potassium, there will be in the metal only 430 metallic atoms, while in the hydrate there will be 700 such atoms. Yet in the latter, besides the 700 metallic atoms, there will be an equal number of aqueous and oxygenous atoms, in all 2800 ponderable atoms. It follows, that if the atoms of potassium are to be considered as minute impenetrable particles, kept at certain distances by an equilibrium of forces, there must be, in a mass of potassium, vastly more space than matter. Moreover, it is the space alone that can be continuous. The non-contiguous material atoms cannot form a continuous mass. Consequently, the well-known power of potassium to conduct electricity must be a quality of the continuous empty space which it comprises, not of the discontinuous particles of matter with which that space is regularly interspersed. It is in the next place urged, that while, agreeably to these considerations, space is shown to be a conductor, there are considerations equally tending to prove it to be a non-conductor, since in certain non-conducting bodies, such as resins, there must be nearly as much vacant space as in potassium. Hence the supposition that atoms are minute impenetrable particles, involves the necessity of considering empty space as a conductor in metals, and as a non-conductor in resins, and of course in sulphur and other electrics. This is considered as a reductio ad absurdum. To avoid this contradiction, Farraday supposes that atoms are not minute impenetrable bodies, but, existing throughout the whole space in which their properties are observed, may penetrate each other. Consistently, although the atoms of potassium pervade the whole space which they apparently occupy, the entrance into that space of an equivalent number of atoms of oxygen and water, in consequence of some reciprocal reaction, causes a contraction in the boundaries by which the combination thus formed is enclosed. This is an original and interesting view of this subject, well worthy of the contemplation of chemical philosophers.
1780. But, upon these premises, Farraday has ventured on some inferences which, upon various accounts, appear to me unwarrantable. I agree that “a” representing a particle of matter, and “m” representing its properties, it is only with “m” that we have any acquaintance, the existence of “a” resting merely on an inference. Heretofore I have often appealed to this fact, in order to show that the evidence of imponderable, no less than of ponderable matter, is precisely the existence of properties which can only be accounted for by inferring the existence of an appropriate matter to which those properties appertain. Yet I cannot concur in the idea that, because it is only with “m” that we are acquainted, the existence of “a” must not be inevitably inferred, so that bodies are to be considered as constituted of their materialized powers. I use the word “materialized,” because it is fully admitted by Farraday, that by dispensing with an impenetrable atom “a” we do not get rid of the idea of matter, but have to imagine each atom as existing throughout the whole sphere of its force, instead of being condensed about the centre. This seems to follow from the following language:
1781. “The view now stated of the constitution of matter would seem to involve necessarily the conclusion that matter fills all space, or at least the 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 matter.”
1782. Literally, this paragraph seems to convey the impression, that, agreeably to this new idea of matter, the sun and his planets are not distinct bodies, but consist of certain material powers reciprocally penetrating each other, and pervading a space larger than that comprised within the orbit of Neptune. We do not live upon, but within, the matter of which the earth is constituted, or rather within a mixture of all the solar and planetary matter belonging to our solar system. I cannot conceive that the sagacious author seriously intended to sanction any notion involving these consequences. I shall assume, therefore, that, excepting the case of gravitation, his new idea of matter was intended to be restricted to those powers which display themselves within masses at insensible distances, and shall proceed to state the objections which seem to exist against the new idea as associated with those powers.
1783. Evidently the arguments of Farraday against the existence, in potassium and other masses of matter, of impenetrable atoms endowed with cohesion, chemical affinity, momentum, and gravitation, rest upon the inference that in metals there is nothing to perform the part of an electrical conductor besides continuous empty space. This illustrious philosopher has heretofore appeared to be disinclined to admit the existence of any matter devoid of ponderability! The main object of certain letters which I addressed to him was to prove that the phenomena of induction could not, as he had represented, be an “action” of ponderable atoms, but, on the contrary, must be considered as an affection of them consequent to the intervention of an imponderable matter, without which the phenomena of electricity would be inexplicable. This repugnance to the admission of an imponderable electrical cause, has been the more remarkable, as his researches have not only proved the existence of prodigious electrical power in metals, but likewise that it is evolved during chemico-electric reaction, in equivalent proportion to the quantity of ponderable matter decomposed or combined.
1784. According to his researches, a grain of water, by electrolytic reaction with four grains of zinc, evolves as much electricity as would charge fifteen millions of square feet of coated glass when supplied by a plate machine of fifty inches in diameter. But in addition to the proofs of the existence of electrical powers in metals thus furnished, it is demonstrated that this power must be inseparably associated with metals, by the well-known fact that in the electro-magnetic machine—an apparatus which we owe to his genius, and the mechanical ingenuity of Pixii and Saxton—a coil of wire, being subjected to the inductive influence of a magnet, is capable of furnishing, within the circuit which it forms, all the phenomena of an electrical current, whether of ignition, shock, or electrolysis.
1785. The existence in metals of an enormous calorific power must be evident from the heat evolved by mere hammering. It is well known that by a skilful application of the hammer, a piece of iron, between it and a cold anvil, may be ignited. To what other cause than their inherent calorific power can the ignition of metals by the discharge of a Leyden battery be ascribed?
1786. It follows, that the existence of an immense calorific and electrical power is undeniable. The materiality of these powers, or of their cause, is all that has been questionable. But, according to the speculations of Farraday, all the powers of matter are material; not only the calorific and electrical powers are thus to be considered, but likewise the powers of cohesion, chemical affinity, inertia, and gravitation, while of all these material powers only the latter can be ponderable!
1787. Thus, a disinclination on the part of this distinguished investigator to admit the existence of one or two imponderable principles, has led him into speculations involving the existence of a much greater number. But if, while the rest of the properties of the metal are represented by Newtonian atoms, the calorific and electrical powers be both material and imponderable, and of these such enormous quantities exist in potassium, as well as in zinc and all other metals, so much of the reasoning in question as is founded on the vacuity of the space between the metallic atoms is groundless.
1788. Although the space occupied by the hydrated oxide of potassium comprises 2800 ponderable atoms, while that occupied by an equal mass of the metal comprises only 430, there may be in the latter proportionally as much more of the material, though imponderable, powers of heat and electricity, as there is less of matter endowed with ponderability.