Intra-Mercurial Planets–Prof. Stewart's 24.011d. Period, Leverrier's and Gaillot's 24.25d., and Leverrier's 33.0225d. Sidereal Periods Considered

Abstract

AS your regular monthly numbers did not reach our Free Library from September, 1881, until comparatively recently, and I was absent from home when they did arrive, it was only quite lately that I had an opportunity of seeing Prof. Balfour Stewart's very interesting paper “On the Possibility of Intra-Mercurial Planets,” read at last year's meeting of the British Association, and published at length in your issue of September 15, 1881. “The possibility” has been almost an admitted fact for over a century, but Prof. Stewart's valuable paper discusses the relation of certain sun spot periods to a probable sidereal period, approximately at least, of an Intra-Mercurial planet of 24.011 days.