The Great Nebula in Andromeda

Abstract

FEW objects in the heavens have been treated with such unmerited neglect as this which has not inaptly been termed the Queen of the Nebulæ. Notwithstanding its enormous magnitude, spreading out, as followed by the Harvard 15-inch achromatic, to 21/4° in length, (according to Bond—Trouvelot gives more), with a breadth of upwards of 1°; and its conspicuous brightness, readily perceptible with the naked eye, it has received little comparative notice. The reason probably may be the pertinacity with which it has hitherto resisted all inquiry, and defied the efforts of the most powerfully armed inves tigation; so that it seems to have been left on one side, as too unpromising for more than casual inspection. This however bears the character of a premature conclusion. Direct examination by the most powerful telescopes has done very little to solve the mystery of its nature. The reply extorted by the spectroscope is but partially intelligible. But we must not therefore despond. The negative or ambiguous results hitherto obtained do not preclude—on the other hand they rather invite—attempts of a different kind. If again defeated, we are only where we were before. If in any measure successful, we may indeed find the mystery only increased by partial solution; but such, after all, is the progress and the limit of all earthly knowledge. An obvious line of inquiry presents itself in the present instance, which seems not to have been adverted to in modern times—the possible evidence of variation either in form or brightness; and the following notices, neither as exhaustive nor as minute as the subject would otherwise admit, have been chiefly put together with this view,