There are, however, other comets which appear once, or it may be several times only, and then disappear out of the solar system for ever. Now the question arises, as to whether the orbits of the comets which are so variable can be explained by the motions of the Aether which we have already ascribed to it? We have seen ([Art. 109]) how it is possible to account physically for the plane of the ecliptic from the motions of the Aether, and how it is that all the planets move within that plane, but here we have a phenomenon of a different kind, as observation distinctly teaches us that the comets do not move in, or keep within the plane of the ecliptic, but gravitate round the sun at all angles to that plane.

In order for us, therefore, to be able to account, and that on a philosophical basis, for this fact, we must revert to our conception of the sun in its relation to the solar system. In [Art. 88] we learned that the sun was an electro-magnet possessing its electro-magnetic field, and generating electro-magnetic waves which were radiated forth from it on every side. From [Art. 89] we learn that an electro-magnetic body possesses lines of force, and that these lines of force take various directions as they are generated by the body, as proved by Faraday's illustrations. Further, a moving electro-magnet, as the sun for example, carries its lines of force with it, as proved by Maxwell.

Now these lines of force extend not only east and west, but also north and south, as depicted in Fig. 29.

Hitherto we have only dealt with the lines of force proceeding from the sun equatorially, which lines form the plane of the ecliptic. We have, now, to take into consideration those lines which extend out into space, north and south of that plane. These are not so curved as the others, but are more inclined to be straight, or less curved, as they are really parts of large curves which extend much further outwards into space.

The orbits of the Short or Long Period Comets can be explained by the fact that they perform their journey more or less in the plane of the ecliptic, though in some cases at a much greater angle than that of any of the planets. Provided, however, they remain within the influence of the electro-magnetic field of the sun, there is then a physical explanation as to their orbital motion round the sun, in a similar way to the orbital motion of the planets, though at greater angles to the plane of the ecliptic.

For we have to remember, that wherever the electro-magnetic waves of the sun's electro-magnetic field extend, there we have also the rotation of that field round its central body, though with a continually decreasing intensity, as already pointed out. Wherever, therefore, we get rotatory Aether currents, due to the rotation of the electro-magnetic field, there we get the conditions which would enable any kind of gaseous or material body to be circulated round the sun. The case, however, of comets which do not return has to be viewed from a different standpoint. Here it seems to me we are dealing with masses of condensed Aether that come within the inductive influence of the electro-magnetic waves of the sun, as that body moves through space with its velocity of about 500,000 miles per day. We have to conceive of this condensed Aether situated north and south of the plane of the ecliptic, and situated probably millions of miles away. As the sun moves onward in its journey through space, carrying its electro-magnetic field with it, then, by the inductive action of the sun, the comet would be attracted by that body, and so would be gradually drawn towards it.

Under this inductive influence it would rush towards the sun, until, approaching very close to it, it would be repelled by the electro-magnetic waves or centrifugal force of that body, and be hurled again by their repulsive energy far far away into space to the north or south of the plane of the ecliptic. As it was moving away from the syn, north or south of the ecliptic, the sun would be moving onwards through space in the plane of the ecliptic, which would practically be at right angles to the motion of the comet, so that by the time the comet had receded far into the depths of space, the sun with its electro-magnetic field would have moved on also in a direction at right angles to the comet's motion.

The effect of the sun's orbital motion would be, that it would be unable to again exert sufficient inductive power upon the comet to bring it within its inductive influence once more. For example, suppose there is a mass of Aether condensing at point A in interstellar space situated some millions of miles north of the plane of the ecliptic, which is represented by the straight lines B C. The sun is moving in the direction towards the part of space represented by point B. We will suppose that when the sun is near point C the mass of Aether at point A is too far away to be appreciably influenced by the inductive action of the sun. But as the sun moves towards point F, then the condensed Aether, which practically forms the body of the comet, will come within its influence and be drawn towards the sun, at an angle to the plane of the ecliptic.

By the time the body of the comet has reached the sun, it will have acquired a momentum which enables it to rush past the sun, and then it will be repelled by the electro-magnetic waves in the direction of F G, which is still at an angle to the plane of the ecliptic; but its motion, combined with the repulsive power of the electro-magnetic waves, is carrying it outside the sphere and influence of the sun's electro-magnetic field. At the same time the sun is proceeding onwards through space, leaving the comet far behind, so that by the time the comet has reached the confines of the solar system, it has either passed under the influence of another star, or has become further condensed to form a meteor, which begins to circle around the largest and nearest body. I do not assert that this hypothesis is strictly correct, but it seems to me that only on some such hypothesis can the appearance and apparent loss of irregular comets be explained.