540

44 4 Abstracting from the loss of the sun’s substance by theemanation of light, is there any cause why the solar system maynot last for ever?’

44 Accidentally reading the other day a book entitled 4 Obser-vations on the Liturgy,’ printed by Debret , 1789, I met with thefollowing note : — 4 The late discovery of the Prussian astro-4 nomer Euler , that the earth in every revolution, narrows its4 orbit, and draws nearer to the sun, and consequently will, in a4 course of years, come within its vortex, and be consumed by it.’You, I am sensible, have written so well on the disturbing forcesprevailing in the planetary system, that I can apply to no one solikely to inform me to what it is that Euler attributes the diminu-tion of the earth’s orbit, and whether it is a constant diminution, orcontained within certain limits. I beg pardon for this intrusionon your time, but I have not Euler ’s works in this retirement.

44 I should have been happy to have directed this letter to youas Astronomer Royal.

. 44 I am, &c.

44 R. Landaff.”

Dr. Vince favoured me with an intelligent and complete answerto my enquiry, by informing me, that he remembered Euler ’shypothesis of the planets moving in an etherial fluid, which gra-dually retarding their motions, would at length carry them to thesun, but that the existence of such a fluid was a mere conjecture ;that there were no irregularities, (as they were called,) in thesystem; that nothing went on continually increasing or decreas-ing, so as to bring on destruction to the system ; but that anyother law of gravitation than the inverse square of the distance,