will therefore be to move the electricity, situate round pks, towards nn, and would do so, were it not for the opposing attractive force of the air, as above explained.

(27.) Action and reaction being equal, this greater amount of attraction also tends to draw the solid matter at section nn towards the electricity round pks, and, as a consequence of the union of section nn with the rest of the cylinder, to move the whole of the cylinder in the line or direction towards o.

(28.) Causes exactly similar, and equal to those considered as operating on one-half the cylinder, operating also on the other half, the tendency of the cylinder to move towards o is counteracted and balanced by an equal and contrary tendency of such other half, in the opposite direction.

(29.) The two halves of the cylinder, being separated through the transverse plane ler, and suspended by silk threads, will then no longer oppose and restrain each other's motion; but obeying their separate and opposite tendencies, RECEDE from each other. Thus might take place a perfect recession of two electrised bodies from each other, without reference to a power so anomalous as is that of repulsion, particularly when referred to the negative state of electricity.

(30.) As the right half of the cylinder moves towards o, the balls included between the stationary medial plane ler, and the parallel plane mkt, considered as moving with the cylinder, become increased in number, and less and less influenced by the inductive action of the electricity of the other, now more distant, half of the cylinder ; while the quantity of solid attracting matter exterior to the cylinder, on the side vv of the plane mkt, is not increased.

(31.) Several consequences flow from this increase in the number of balls or quantity of solid matter between the medial stationary plane ler, and the moving plane m k t, and each of such consequences flows from the other or others before it, in the following order :

(a) An increase in the attraction or inductive influence exerted on the electricity of the first stratum of balls round nn, by the solid matter of the increased number of more remote balls.

(b) An increase in the attraction of the solid matter of such first stratum of balls, for the electricity of the cylinder about nn.

(c) An increase in the depth of the film of electricity about nn, at the expense of the mass of it at vv, and elsewhere on the side of m kt, towards h.

(d) A diminution of the excess in the depth of the electrical film at vv, over that at nn.

(e) A diminution of the excess of attraction exerted between the solid matter of section vv, of the cylinder and its electricity, over that exerted between section nn and its electricity.

(f) A diminution of the excess of the attraction of such solid matter at nn, for the electricity round the plane or section pks, over that of the solid matter at vv, for the same electricity.

(g) A diminution of the tendency of that electricity, and the solid matter of the section nn, to approach each other.

(h) And, lastly, a diminution of the tendency of this half of the cylinder to recede from the other.

(32.) In lieu of the two half cylinders, I will now examine the case of two balls, equally electrified positively, b 1 and b 2, fig. 5, which (the foregoing explanations being admitted) must divide the inductive attractions of the balls a and c between them. Here b 1 will be in the situation of an adjacent ball to b 2, as also b2 to b1, and the observations on propositions 9 (3), 10 (4, 5, 6), 13 (7), 14 (8), 15 (10), and fig. 2 (11, 12), where c was a body adjacent to b, apply in the same manner to shew that the free and increased electricity of b 1, fig. 5, must now stand out or be elongated on its side remote from b 2, as the free and natural portion of a and c, fig. 2, stood out on the sides remote from b; b1 and b 2, fig. 5, being equally electrified, any observation applying to one must apply equally to the other.

(33.) The two balls, b1 and 62, if kept in contact, act very nearly as if they were one elongated body, like the above-mentioned cylinder, fig. 4; and well known experiments having proved that such a body has a deeper bed, or accumulation of electricity, at its ends than elsewhere, support the foregoing partly theoretical conclusions. Let the two halves of the cylinder in fig. 4, and the balls b1 and 62, in fig. 5, change places, and it will be seen that the above observations will, with a trifling allowance, still apply to each figure under such a change of circumstances.

(34.) I have thus far spoken of metallic balls for the sake of more easy comprehension, (without noticing the influence of the air,) but think the observations hitherto made will apply equally to the atoms of the atmosphere, which are, by some yet unexplained means, insulated from each other. That they, in their natural state, possess free electricity, is shewn by a point on a conductor electrified negatively, and I suppose it adheres to them as it does to a metallic ball. If they be chemically compounded, and consequently not spherical (speaking of their component atoms of oxygen and nitrogen only), those component atoms probably present spherical or otherwise curved terminations, and answer every purpose of the present question. I shall therefore take the circles in the figures given as their representatives, and consider either a metallic ball, or one of such atmospheric atoms, positively electrified, will produce the same inductive influence, or disturbance of equilibrium, amongst other atmospheric atoms, as one electrified metallic ball amongst others unelectrified, and consequently the same elongations of their films of free electrical liquid, in a direction from the positively electrified ball or atom, towards each next adjacent atom. (35.) Returning to the case of two electrified balls. Let two such balls as b and c, fig. 6, be positively electrified, suspended as the common pith ball electroscope, and surrounded as usual by

atmospheric atoms, of which a few only are represented by the circles ade, 1, 2, 3, &c. Let the lines rs, tu, v x, y z, mn, represent vertical planes perpendicular to an imaginary straight line, passing through the centres of b and c, and each adjacent pair inclosing equal spaces. Let the two outer of those spaces be called respectively the outer b and c spaces, and the others the inner b and c spaces. Let also the imaginary planes, tu and yz, passing through the centres of b and c, be imagined also to recede when, and as those balls recede; and the planes rs, mn, to do the like, but twice as rapidly; so as to preserve the same equality of distance between every two adjacent planes, at each instant during the recession of the balls.

(36.) Let the electricity be-First, (supposed for the sake of argument,) equally diffused over each ball, even when the balls are brought near each other.

Secondly, distributed unequally by inductive action; and
Thirdly, causing the balls to recede from each other.

(37.) First, The electricity supposed equally diffused over each ball, as I suppose it would be, if left to the undisturbed action of the balls alone, and under this head

The solid matter of

As to atom e, midway between b and c. b and c, being required to exert increased attraction by an additional quantity of free electricity upon themselves, loses a portion of its natural attraction for the free natural electricity of e (prop. 10). That electricity is therefore left at liberty to exert increased attraction for the common matter of all the circle of next adjacent atmospheric atoms (which includes atom i,) in the plane vx, and other atoms next adjacent to e, near that plane, (proposition 13,) under the words vice versa.

The electricity of e will thereby be partly accumulated in a circle round it, in and near the medial plane vx, and evince a tendency to escape to atom i, and the other atoms similarly situated (prop. 15.) This atom, e, will thus be attracted by means of its electricity, by equal forces towards every atom next adjacent to it in the plane vx, and by other equal forces by means of its common matter towards b and c.

(38.) The electricity of atom 2, and the other atmospheric atoms, whose common matter is thus acted upon by atom e, will at the same time act on the next larger circle of atoms, including atom 2, and those adjacent to such circle last mentioned, (prop. 14 and 13.)

(39.) As to atom d. The common matter of this atom corresponds to that of c, in figs. 2 and 5, and is subject to the same observations, and therefore is attracted by the electricity of c, fig. 6, with great force, in that direction; while its own electricity is attracted with great force in the opposite direction, or away from c, by the other atoms in that direction, which are acted upon in a similar manner by the next in succession, and so forth. The same observations apply to atom a, with respect to the ball b.

(40.) As to atoms 1 and 2. These atoms, and all other situate

in the plane vx, equidistant from b and c, form the boundary dividing the respective ranges of predominant inductive action exerted by b and c; both 1 and 2, and their electricity, being as equally subject to the separate inductive action of b and its electricity, as to that of c and its electricity.

(41.) As to atom 3. The electricity of atom 3, and all others situate in the plane, y z, must lean a little to the right of y z, as represented, there being a preponderance of atmospheric atoms on that side, capable of being acted upon, and reacting, by induction.

(42.) This preponderance may perhaps appear more distinctly, by observing that the outer c space is equal to the inner c space; but the action of the electricity of c, on the atoms in its inner space, being counteracted by the inductive action of the electricity of b, while there is little or no such counteraction in the outer c space, the action of the atoms in the latter space may be certainly concluded to exceed the action of those in the inner space. The whole of the atoms to the right of m n may then be considered as adding to this excess, by exerting a great preponderating force, both in direct and oblique directions, only from c, without any counterbalancing force tending towards c.

(43.) Were there such a counter force, it could only be found to the left of vx; but, that such a compensating force cannot be found there, appears certain; for the electricity of b must act on the common matter of the atoms there, and neutralise, or at least balance, by their propinquity, all the effects, either immediate or inductive, of that common matter, on the electricity of c. The preponderating force, to the right of m n, will consequently incline the deepest part of the film of electricity of atom 3 to the right of y 2.

(44.) So far as to the electricity of b and c, considered as equally diffused.-Now,

Secondly, As to a new distribution by induction.-Before this new distribution, the electricity on the two contiguous hemispheres of the balls, acting conjointly on all the atmospheric atoms in the plane v x, while the atoms in the plane m n were acted on (at least, near the balls) by the outer hemisphere of c only, a greater amount of induction, or disturbance of equilibrium, must take place on the atoms in the plane v x, than on those in the plane m n; and consequently, give the former the stronger tendency to part with their electricity.

(45.) Though there be this joint action of the electricity of the two inner hemispheres of the balls on the atoms in the plane v x, yet a moiety of this action cannot equal the action capable of being exerted by the electricity of one of such inner hemispheres, if acting alone and unopposed; and, consequently, such moiety will not equal the action exerted between the electricity of the outer hemisphere of c and the atoms in the plane m n; and, in the same manner, a moiety of the actions of the electricity of the two inner

spaces, will not equal the action of the electricity of the outer hemisphere of c, on the atoms in the outer c space.

(46.) Therefore, on the electricity of b and c being released from the unnatural assumed distribution, and the natural forces allowed to operate, the preponderance of inductive force in the outer c space, must draw a greater portion than half of the electricity of c to its outer hemisphere; and when, to this drawing force, we add the totally unbalanced attractive force of the atoms to the right of m n, very little electricity can be left on the inner hemisphere of c. All the foregoing observations, as to the ball c, &c., apply, of course, equally to the ball b, &c.

(47.) Thirdly, As to the ultimate effect, the recession of the balls from each other.-The said preponderant force, existing on the right of m n, acting, by its inductive influence, through the atoms in the outer c space, and drawing the electricity of c in that direction, and the continual attraction of the electricity of c for the solid matter of c itself operating as shewn by fig. 4, (25, 6, 7,) tending to draw that solid matter into the centre of its film of electricity, while exactly similar forces are exerted on the ball b, and its electricity in the opposite direction, the recession of b and c from each other necessarily results.

(48.) As the ball c, and, consequently, the plane y z, recede from the stationary medial plane v x, an increased number of atmospheric atoms must become included between those two planes, that is, in the inner c space, and require a doubly rapid removal of the imaginary plane, m n, to include an equal additional number of atmospheric atoms in the outer c space, to balance the increased numbers in the increased inner c space. This process lessens the preponderant force to the right of mn, or beyond the outer c space, by increasing the distance of the atoms which, for the time, exert that force, and will so continue to lessen that preponderant force, till it is so far reduced as to be balanced by the gravity of the ball and the action of the thread supporting it.

(49.) To assist in such process, there is of course, at the same time, a progressive return of electricity to the contiguous sides of the balls, in proportion to the increased number of atoms, capable of induction, which have become included in their inner b and c spaces, as explained with respect to the receding halves of the cylinder, fig. 4, (30, 31.)

(50.) It may not be entirely useless, nor uninteresting, to inquire how far the balls might possibly recede from each other, supposing the supporting thread removed, the balls in an atmosphere of indefinite extent in every direction, of equal density, and perfect mobility.

(51.) If the law (which, I believe, is generally considered as settled), that electrical attraction, and what is called repulsion, are inversely as the square of the distance, be true, then a single electrified ball, placed in the supposed indefinite atmosphere, must