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. [Illustration: Fig: 30.] 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. ART. 113. _Short Period Comets and Long Period Comets._--We have seen in the previous article, that some Comets revolve round the sun in closed orbits of exceeding great eccentricity, and the return of these may be calculated with certainty. There are about two dozen comets which revolve around the sun, and which return at intervals lying between three years and 76 years. This class of comets may be divided into two kinds, which are known as Short Period Comets and Long Period Comets respectively. The following table gives a list of the chief of the Short Period Comets, together with some particulars relating to time of revolution, etc.:-- COMETS. PERIOD OF PERIHELION APHELION REVOLUTION. DISTANCE. DISTANCE.