The Moon | Page 2

invaluable
notes in "Celestial Objects for Common Telescopes," and in various
periodicals, by the late REV. PREBENDARY WEBB, to whom
Selenography and Astronomy generally owe so much, have also been
consulted.
As a rule, all the more prominent and important features are described,
though very frequently interesting details are referred to which, from
their minuteness, could not be shown in the map. The measurements
(given in round numbers) are derived in most instances from
NEISON'S (Nevill) "Moon," though occasionally those in the
introduction to Schmidt's chart are adopted.
THOMAS GYWN ELGER. BEDFORD, 1895.
CONTENTS
INTRODUCTION MARIA, OR PLAINS, TERMED "SEAS" RIDGES
RING-MOUNTAINS, CRATERS, &C. Walled Plains Mountain Rings
Ring-Plains Craters Crater Cones Craterlets, Crater Pits MOUNTAIN
RANGES, ISOLATED MOUNTAINS, &c. CLEFTS, OR RILLS
FAULTS VALLEYS BRIGHT RAY-SYSTEMS THE MOON'S
ALBEDO, SURFACE BRIGHTNESS, &c. TEMPERATURE OF THE
MOON'S SURFACE LUNAR OBSERVATION PROGRESS OF
SELENOGRAPHY, LUNAR PHOTOGRAPHY
CATALOGUE OF LUNAR FORMATIONS FIRST QUADRANT--
West Longitude 90 deg. to 60 deg. West Longitude 60 deg. to 40 deg.
West Longitude 40 deg. to 20 deg. West Longitude 20 deg. to 0 deg.
SECOND QUADRANT-- East Longitude 0 deg. to 20 deg. East
Longitude 20 deg. to 40 deg. East Longitude 40 deg. to 60 deg. East
Longitude 60 deg. to 90 deg. THIRD QUADRANT-- East Longitude 0

deg. to 20 deg. East Longitude 20 deg. to 40 deg. East Longitude 40
deg. to 60 deg. East Longitude 60 deg. to 90 deg. FOURTH
QUADRANT-- West Longitude 90 deg. to 60 deg. West Longitude 60
deg. to 40 deg. West Longitude 40 deg. to 20 deg. West Longitude 20
deg. to 0 deg.
MAP OF THE MOON First Quadrant Second Quadrant Third
Quadrant Fourth Quadrant
APPENDIX Description of Map List of the Maria, or Grey Plains,
termed "Seas," &c. List of some of the most Prominent Mountain
Ranges, Promontories, Isolated Mountains, and Remarkable Hills List
of the Principal Ray-Systems, Light-Surrounded Craters, and Light
Spots Position of the Lunar Terminator Lunar Elements Alphabetical
List of Formations
INTRODUCTION
We know, both by tradition and published records, that from the
earliest times the faint grey and light spots which diversify the face of
our satellite excited the wonder and stimulated the curiosity of mankind,
giving rise to suppositions more or less crude and erroneous as to their
actual nature and significance. It is true that Anaxagoras, five centuries
before our era, and probably other philosophers preceding him,
--certainly Plutarch at a much later date--taught that these delicate
markings and differences of tint, obvious to every one with normal
vision, point to the existence of hills and valleys on her surface; the
latter maintaining that the irregularities of outline presented by the
"terminator," or line of demarcation between the illumined and
unillumined portion of her spherical superficies, are due to mountains
and their shadows; but more than fifteen centuries elapsed before the
truth of this sagacious conjecture was unquestionably demonstrated.
Selenography, as a branch of observational astronomy, dates from the
spring of 1609, when Galileo directed his "optic tube" to the moon, and
in the following year, in the Sidereus Nuncius, or "the Intelligencer of
the Stars," gave to an astonished and incredulous world an account of
the unsuspected marvels it revealed. In this remarkable little book we
have the first attempt to represent the telescopic aspect of the moon's

visible surface in the five rude woodcuts representing the curious
features he perceived thereon, whose form and arrangement, he tells us,
reminded him of the "ocelli" on the feathers of a peacock's tail,--a
quaint but not altogether inappropriate simile to describe the
appearance of groups of the larger ring-mountains partially illuminated
by the sun, when seen in a small telescope.
The bright and dusky areas, so obvious to the unaided sight, were found
by Galileo to be due to a very manifest difference in the character of
the lunar surface, a large portion of the northern hemisphere, and no
inconsiderable part of the south-eastern quadrant, being seen to consist
of large grey monotonous tracts, often bordered by lofty mountains,
while the remainder of the superficies was much more conspicuously
brilliant, and, moreover, included by far the greater number of those
curious ring- mountains and other extraordinary features whose
remarkable aspect and peculiar arrangement first attracted his attention.
Struck by the analogy which these contrasted regions present to the
land and water surfaces of our globe, he suspected that the former are
represented on the moon by the brighter and more rugged, and the latter
by the smoother and more level areas; a view, however, which Kepler
more distinctly formulated in the dictum, "Do maculas esse Maria, do
lucidas esse terras." Besides making a rude lunar chart, he estimated the
heights of some of the ring- mountains by measuring the distance from
the terminator of their bright summit peaks, when they