Note 146 — PART V. GENERAL VIEWS RESPECTING THE SOLAR SYSTEM.
Reading edition
An interesting paper will be found in the Memoirs of the Astronomical Society, vol. ii. concerning the effect of this resisting medium on the planets. It is there shewn, that, if the density of the ether be supposed 360,000,000,000 times less than that of atmospheric air, the resistance will be sufficient to produce the acceleration observed in the mean motion of Encke’s Comet. On investigating the effect of such a medium upon the movements of the planet Mercury, it is calculated that, in 100 Julian years, there would be a difference of no more than 31″.2 in the mean geocentric longitude of the planet at its inferior conjunction. It is here assumed that the density of the ether diminishes with the square of the distance from the Sun.