their approach to a state of rest, each will exercise its attracting and condensing power to the utmost on the surrounding ether, extending to those distances where gravitation begins to be stronger than cohesive affinity.

Such a state of matter cannot be called gaseous, since all the defining properties of a gas have disappeared. Elasticity and expansiveness are replaced by inelastic repose. The want of intestine motion, either of translation or rotation, will make it resemble solids rather than liquids, while in density it occupies the other extreme; and being saturated with ether, it will approach to the properties of the free ether which it adjoins.

There will thus, according to the present theory of the laws of matter, be more truth than has latterly been recognized in the old arrangement of the four elements, which placed a fourth region of fire above the solid, liquid, and gaseous constituents of our globe. In fact, above the region where the air, though greatly rarified, is still elastic, there must be a still higher stratum where elasticity has wholly ceased, and where the particles of matter, being very widely separated, condense around them the largest amount of ether. All sensible heat, in the collision or oscillation of neighbouring atoms of matter, will thus have disappeared; but latent heat, in the quantity of condensed ether, or repulsive force ready to be developed on the renewed approach of the atoms, will have reached its maximum; and may be capable of producing the most splendid igneous phenomena, like the northern lights, or tropical thunderstorms.

30. To explain the mutual relations of the solid, liquid, gaseous and igneous forms of matter.

The laws of affinity and repulsion imply a first con

stant, or minimum distance, at which two atoms of matter, each charged with one of ether, will be neutral to each other, repelling at less, and attracting each other at greater distances. Chemical or compound atoms are to be conceived as made up of a definite number of these simple atoms, arranged regularly in planes or cycles, so as to exercise polarity at their sides and angles. The solid state of bodies is that in which these compound atoms are attached to each other in permanent positions by their polar qualities, so that a slight increase of distance generates a powerful attractive force, and a slight decrease by pressure a still more powerful force of repulsion. The liquid state is that in which these compound atoms revolve on axes, so that their polarity and fixity of position disappear, and they are able to move amongst each other, while they still continue within the cohesive limit, or their attraction is increased by a slight increase of their mean distance. The gaseous state is when they pass by expansion beyond this limit, and the attraction being lessened by increase of distance, tend continually to separate more widely, and are only restrained within moderate distance by external pressure. The fourth, or igneous state, is that in which gaseous elasticity has ceased through further increase of distance, and the consequent absorption of vis viva, and in which, the solid atoms, having been separated into their planes, and even these, perhaps, into their simple atoms, these last are distributed almost uniformly by the repulsive force of the ether which they have separately condensed around them. 31. RESULTING DEFINITIONS.

Monads are the self-repulsive particles of ether, diffused through all space.

Atoms are the dual particles of matter and ether com

bined inseparably, which constitute the first or ultimate elements of all ponderable substance. They combine in their mutual action the three different laws of general gravitation, cohesive affinity, and ethereal repulsion.

The First Constant, or neutral distance, is that at which two such atoms neither attract nor repel each other, or rather, attract only with the infinitesimal force of general gravitation.

Compound, chemical, or plural atoms, are the ultimate elements on which the constitution of every specific kind of gas, solid, or liquid depends, and must be conceived to consist of a definite number of simple atoms, in some simple or compound arrangement.

Sensible heat is the vis viva of the slight oscillations of solid or liquid atoms, or of the motions of the particles of gas amongst themselves.

Heat of fluidity is the vis viva of the motion of rotation. in the particles of fluids.

Heat of vaporization is the vis viva absorbed in gases, by the separation of their elements to a wider distance, beyond their mean distance in their liquid form.

Heat of chemical combination is the vis viva developed by the new and closer relation of mutual distance, into which the components of compound atoms are brought by their union. Assuming the arrangements to be known before and after that union, its amount will be capable of exact calculation, the laws of affinity and repulsion being also known.

Light consists of vibrations or undulations, transverse to the axis of the rays, propagated through the free ether of space, and transmissible, in some cases, through the substance of solids and liquids either through inter

stices filled with free ether, or the combined ether of the particles themselves.

Electricity consists in the increase or decrease of the mean vis viva of ethereal repulsion between surfaces of material substances, arising from some change or special modification, of those surfaces, with reference to their charge of attached or combined ether.

CHAPTER IV.

ON THE IGNEOUS FORM OF MATTER.

32. To explain the phenomena of the nuclei and tails of Comets.

"There is beyond question," Sir J. Herschel remarks, some profound secret and mystery of nature concerned in these phenomena. Perhaps it is not too much to hope that future observation, borrowing every aid from rational speculation, grounded on the progress of physical science, will ere long enable us to penetrate this mystery; and to decide whether it is really matter in the ordinary acceptation, which is projected from their heads with such extravagant velocity, and directed from the sun as its point of avoidance." He then remarks, on the tail of the comet of 1843, which was brandished unbroken in two hours through an angle of ninety degrees, and still reached to the earth's orbit; that "it is utterly incredible that it is one and the same material object, and that the notion of a negative shadow would best explain it; while still there are many other phenomena, as the issuing of the streamers from the nucleus, which link themselves just as irresistibly with our ordinary notions of matter."