The writer in "Science Gossip" has taken the irregular motions in the nebula as made to his hand, and has come to the same conclusion as we have, namely, that they would all resolve themselves into motion in one direction only, always subject to the general attraction towards the centre of gravity of the nebula, which means motion round a centre, perhaps not necessarily rotary motion. However, the only difference between his ideas and ours is that we deal with a hollow nebular shell, in which, it will be acknowledged, it would be much more easy for the law of attraction to produce marked and distinct motions of any kind, and which would lead to one motion in one direction throughout, than in a nebula homogeneous, or nearly so, from the surface to the centre. Whether it would lead to the formation of an oblate spheroid is another question, as that might depend on a variety of circumstances, one or more of which we shall have to touch later on; in fact, we have already shown how the very reverse might be the case. CHAPTER XVI. PAGE 282 The sun's neighbours still exercise their attraction over him. 283 Regions of greatest density in the 9 nebulæ dealt with; compared with the orbits of the planets made from them. 287 Results of comparison favourable to the theory. 289 Differences of size in the planets have arisen from variations in the quantity of matter accumulating on the nebulæ. 290 Causes of the retrograde motions in Neptune, Uranus, and their satellites. 292 Probable causes of the anomalous position of Neptune. 293 Rises and falls in the densities and dimensions of the planets explained. 295 The form of the nebulæ must have resembled a dumb-bell. 296 More about rises and falls in densities. 297 Reason why the Asteroid nebula was the least dense of the system. 298 Not necessary to revise the dimensions given to the 9 nebulæ. 299 Causes of the anomalies in the dimensions, densities, etc., of the Earth and Venus. 299 The strictly spherical form of the sun accounted for. But it may yet be varied. 300 Repetition that a spherical body could not be made from a lens-shaped nebula by attraction and condensation. TESTING THE PRACTICABILITY OF THE HOLLOW SPHERE THEORY. RETROGRADE MOTIONS, POSITIONS, DENSITIES, MASSES, ETC. ETC., CONSIDERED.