336 J. D. Dana on the Volcanoes of the Moon. 
neous action in their simple grandeur, unaltered and uncompli- 
cated by any attending operations. We may hope therefore to 
find some profit in contemplating for a few moments this land of 
the skies: and although we may not look for very speedy “an- 
nexation,”’ we may possibly gather some facts and ideas which 
the decree of Truth will annex to the domain of Science. 
The moon, as we all know, has been minutely studied ina 
physical point of view, and already some important geological 
conclusions have been drawn from the facts it presents. The al- 
titudes of its mountains were first estimated by Galileo,* and af- 
terwards were mathematically calculated by Heveliust and Ric- 
cioli. Sir Wm. Herschel continued the investigations, and re- 
ported the probable activity of three of its voleanic mountains.{ 
Mayer, Huth, Harding, and Schréter,§ and more lately Gruithui- 
sen and W. G. Lohgmann,|| are other prominent names among 
those who have added largely to our knowledge of the moon’s 
urface. More recently still, MM. Beer and Madler have pursued 
this science of Selenography with wonderful perseverance and 
labor, and have given corrected results of all previous calcula- 
tions, with magnificent maps of the moon’s topography.1 1095 
heights were carefully measured by them, and their features, to 
a great degree of accuracy, ascertained. 'These maps have af- 
forded M. Elie de Beaumont some deductions alledged as sup- 
porting certain geological theories. James Nasmyth, Esq., in the 
Transactions of the Royal Astronomical Society for the present 
* In the article referred to in the Annuaire des Longitudes, (p. 522,) Arag? 
states that Clearchus, on the authority of Plutarch, described the moon as smooth 
and lustrous like a mirror. Democritus attributed ah spots to inequalities of sur- 
face. Galileo first observed the lunar mountains with his telescope in 1610, and 
estimated their height at one twentieth of the diameter, giving 8800 me etres for 
ee altitude, which but little exceeds their actual height. 
J. Hevelius, Selenographia ; St. y Gadent; I 1647. 
t Phil. Trans. fort 780, p- 507, Ot i lating to the Moon: 
—for 1787, p. 229, An Account of Three Volcanoes in the Moo n:—for 1794, p- 
39, Account of some particulars observed during the late Lgegee (in 1793) of the 
Bun. 
§ J. H. Schréter, Selenotopographische Fragmente zur genauern Kenntniss 
Mondilache ihrer erlittenen Veranderungen und Atmosphire ; 2 vols, 4to, Gottin- 
gen, 1791 and 1802.—Gruithuisen, in Bode’s Astron. Jahrb., 1825. 
|| Topographie der sichtbaren Mondoberfiactie: von W. G. Lobrmann; 410, 
Dresden und Leipzig, 1824. 
1 ao ee vergleichende Selenographie; mit besonderer Beziehung auf die 
pees Sy ee Mappa selenographica, von W. Beer u : 
ai © Mt Mia: Berlin, 1837. 
