of stars that until then were supposed to be mere clouds of luminous matter. The exact forms of other nebulæ have also been accurately determined by this telescope, which fully deserves the glowing eulogium passed upon it by the Duke of Argyle in his presidential address at the meeting of the British Association at Glasgow, in 1855. "This instrument," said his Grace, "in extending the range of astronomical science as it has done, has been the means of throwing certain doubts upon the laws that govern the motions of the heavenly bodies, and render it possible that certain of the far-distant nebulæ are regulated in their movements by other laws than those to which the members of our own system are subjected."
The clearness with which this telescope exhibits every object within its range is so great that the most distant nebulæ are seen with as great distinctness as the nearest planet. On directing it towards the moon, which is only distant from us about 240,000 miles, the surface of our satellite may be explored with a facility almost as great as that with which we examine the details of a landscape with an ordinary telescope.
Maedler, a German astronomer, who has measured nearly every mountain and valley on the moon's surface with the greatest exactitude, stated some years before Lord Rosse's telescope was perfected that if a monument as large as one of the Pyramids existed on the surface of the moon it could have been readily distinguished by the instruments then in use. With Lord Rosse's telescope we can see the surface of our satellite so much enlarged that a space 220 feet square could be readily perceived by a good observer. This enormous eye, measuring 6 feet in diameter, would hardly show us a lunar elephant; but it is certain that if a troop of buffaloes, or animals analogous to them, crossed the field of vision, they would undoubtedly be perceptible.
