slowly (through chemical attraction), then more rapidly (through the so-called Newtonian attraction), and always in proportion as its mass increases, draws the surrounding parts more and more strongly to unite with itself." This central body is not strictly to be called a sun at the outset, for it is not yet "in a flaming state"; this it only gradually becomes as, in the course of the subsequent processes of readjustment, "the lighter and more volatile portions of the primitive matter," failing to maintain a movement of periodic revolution, drop into the center of attraction. (2) The formation of a whirl of unaggregated particles moving round this central body in circular but separate and intersecting orbits.
When the mass of the central body has grown to such a point that the velocity with which it draws particles to itself from great distances is, by the weak degrees of repulsion with which the particles impede one another, deflected into lateral motions which, by virtue of centrifugal force, encompass the central body in an orbit—then there are produced great whirls of particles, each of which, by reason of the composition of the gravitational force and the force making for deflection sideways, describes a curved line. These orbits all intersect one another. . . and are in conflict with one another.
(3) The transformation of this disordered whirl of particles into a ring or disc of particles moving in free, parallel, circular orbits round the central body. The conflicting movements of the preceding stage come eventually to such an adjustment that they interfere with one another as little as possible. This happens in two ways:
First, by the particles limiting each others' movements till they all advance in one direction; second, by their limiting their vertical movements towards the center of attraction till, all moving horizontally in parallel circles round the sun as their center, they no longer intersect one another's paths, and, by the equalization of the centrifugal and centripetal forces, they maintain themselves constantly in free circular orbits. In this state, when all the articles are moving in one direction and in parallel circles, the conflict and collision of the elementary bodies is annulled, and all things are then in the condition of least reciprocal interference.
Further, "in acordance with the laws of centrifugal motion, all these revolutions must intersect the center of attraction with the plane of their orbits"; and for bodies moving in a common direction round a common axis, there is only one such plane. Therefore, the revolving particles gather about "that circle which passes through the rotation of the axis in the center of the common attraction," and the system assumes (though there are as yet no planets) that discoid form characteristic of our present planetary system. (4) The gradual formation, within this ring, of planets, through the attractions subsisting between the separate particles composing it. Kant has hitherto treated attraction chiefly as operative between the central mass and the particles; between particle and particle the relation has been one of repulsion. But at this point, "the attraction of the elementary bodies for one another begins to produce its effect, and thereby gives the start to new
