THE INTRA-MERCURIAL PLANET.

Globe, Volume VIII, Issue 863, 31 March 1877, Page 3

THE INTRA-MERCURIAL PLANET.

The following letter appeared in the Times with respect to this planet: TO THE EDITOR OF THE TIMES. Sir, —In reference to the supposed intraMercurial planet, the transit of which across the sun'B disc may possibly occur 21st to 23rd March, and whicn has formed the subject of a communication from the AstronomerBoyal, Sir George Airy (not Lord Airy), a few facts may not be uninteresting to your readers. Le Verrier, so well known in connection with the discovery of Neptune—generally considered to be the grandest achievement of the human intellect —in his planetary researches discovered an error in the perihelion of Mercury amounting to only thirty-one seconds in a century; he concluded from this that the mass of Vetus was at least one-tenth greater than commonly assumed, or that there existed some unknown planet or planets between Mercury and the sun. This was as far back as 1859. On this becoming known, a Dr I>scarbault, in France, stated that he had on March 29th observed a transit of an object across the sun's disc. Le Verr er visited Lescarbault, and after critically examining his instruments and figures, became satisfied that an intra Mercurial planet had been observed. Soon after the supposed planet was named Vulcan, and approximate estimates computed by which it would appear that he revolves round the sun in 19 days 17 hours, at a mean distance of about fourteen millions of miles from the sun. The new planet would thus travel in his orbit at the astounding rate of more than three thousand miles in a minute. It appears that transits can only occur in March and September. Any moderately good telescope will probably show the transit if it occurs. Should the existence of the planet prove a fact, it will be yet another triumph of modern science. Yours, &c, A. P. Austin, F.R.A.S.