An Intra-Mercurial Planet

Abstract

WITH reference to the important announcement, by telegram, of the discovery by Mr. Watson of an intra Mercurial planet during the late eclipse of the sun, it may he worth remarking that the position of θ Cancri agrees very well with that given in the telegram published in NATURE, and that there may be a possibility that the object observed is in reality this star. The position of the suspected planet recorded by Mr. Watson is R.A. 8h. 26m., and N.P.D. 72°; the apparent place of the star, computed from the mean place given in the new Nine-Year Catalogue for 1872, January 1, is, for July 29, R.A. 8h. 24m. 40s., and N.P.D. 71° 29 40. The magnitude of this star is, however, smaller than that given by Mr. Watson, that in the British Association Catalogue being 5½, and that in Argelander's Uranometria Nova 6. This discrepancy may very easily occur in the hurry of such a sensational observation, as on these occasions the time at the disposal of the observer is so limited.