condition, to the efficiency of atmospheric
protection against meteoric bombardment; and Mr. Pickering shows that it
could be afforded by such a tenuous envelope as that postulated by him.

The first to emulate Schroeter's selenographical zeal was Wilhelm
Gotthelf Lohrmann, a land-surveyor of Dresden, who, in 1824, published
four out of twenty-five sections of the first scientifically executed
lunar chart, on a scale of 37-1/2 inches to a lunar diameter. His sight,
however, began to fail three years later, and he died in 1840, leaving
materials from which the work was completed and published in 1878 by Dr.
Julius Schmidt, late director of the Athens Observatory. Much had been
done in the interim. Beer and Maedler began at Berlin in 1830 their great
trigonometrical survey of the lunar surface, as yet neither revised nor
superseded. A map, issued in four parts, 1834-36, on nearly the same
scale as Lohrmann's, but more detailed and authoritative, embodied the
results. It was succeeded, in 1837, by a descriptive volume bearing the
imposing title, _Der Mond; oder allgemeine vergleichende Selenographie_.
This summation of knowledge in that branch, though in truth leaving many
questions open, had an air of finality which tended to discourage
further inquiry.[927] It gave form to a reaction against the sanguine
views entertained by Hevelius, Schroeter, Herschel and Gruithuisen as to
the possibilities of agreeable residence on the moon, and relegated the
"Selenites," one of whose cities Schroeter thought he had discovered, and
of whose festal processions Gruithuisen had not despaired of becoming a
spectator, to the shadowy land of the Ivory Gate. All examples of change
in lunar formations were, moreover, dismissed as illusory. The light
contained in the work was, in short, a "dry light," not stimulating to
the imagination. "A mixture of a lie," Bacon shrewdly remarks, "doth
ever add pleasure." For many years, accordingly, Schmidt had the field
of selenography almost to himself.

Reviving interest in the subject was at once excited and displayed by
the appointment, in 1864, of a Lunar Committee of the British
Association. The indirect were of greater value than the direct fruits
of its labours. An English school of selenography rose into importance.
Popularity was gained for the subject by the diffusion of works
conspicuous for ingenuity and research. Nasmyth's and Carpenter's
beautifully illustrated volume (1874) was succeeded,