Bond of Harvard University; to Rutherford's (of New York) unparalleled lunar photographs; and finally to Nasmyth and Carpenter's wonderful work on the Moon, illustrated by photographs of her surface in detail, prepared from models at which they had been laboring for more than a quarter of the century.
Of all these maps, pictures, and projections, Barbican had provided himself with only two--Beer and Maedler's in German, and Lecouturier and Chapuis' in French.

These he considered quite sufficient for all purposes, and certainly they considerably simplified his labors as an observer.
His best optical instruments were several excellent marine telescopes, manufactured especially under his direction.

Magnifying the object a hundred times, on the surface of the Earth they would have brought the Moon to within a distance of somewhat less than 2400 miles.

But at the point to which our travellers had arrived towards three o'clock in the morning, and which could hardly be more than 12 or 1300 miles from the Moon, these telescopes, ranging through a medium disturbed by no atmosphere, easily brought the lunar surface to within less than 13 miles' distance from the eyes of our adventurers.
Therefore they should now see objects in the Moon as clearly as people can see the opposite bank of a river that is about 12 miles wide.
[Footnote A: In our Map of the Moon, prepared expressly for this work, we have so far improved on Beer and Maedler as to give her surface as it appears to the naked eye: that is, the north is in the north; only we must always remember that the west is and must be on the _right hand_.] [Footnote B: In our Map the _Mappa Selenographica_ is copied as closely and as fully as is necessary for understanding the details of the story.
For further information the reader is referred to Nasmyth's late magnificent work: the MOON.].