284 
EASTMAN. 
can Association for the Advancement of Science to disprove 
the theory that meteors had their origin in lunar valcanoes. 
Assuming that a lunar volcano,may eject masses of matter 
with the requisite velocity to pass beyond the region where 
the lunar gravitation predominates over the terrestrial and 
the masses become obedient to the earth’s attraction, Dr. 
Gould examines in detail the consequences to which the 
theory of the lunar origin of meteorites would necessarily 
lead, and presents his conclusions as follows: 
“ From the foregoing considerations we are warranted in 
assuming that for every body expelled from lunar volcanoes 
with a force adapted for throwing to the earth an aerolite of 
average dimensions there are, in probability, at the very 
least one hundred and eighty bodies expelled with forces 
not thus adapted; that for every mass ejected with the av¬ 
erage force of a lunar volcano and striking the earth, there 
are at least one hundred and eighty masses of inadequate 
dimensions ejected; and that for any given combination of 
volcanic force and projected mass, the region of the lunar 
surface, whence the mass may reach the earth, is exceeded 
in extent by the tract of the lunar surface whence this would 
be impossible, in the ratio of fifty to one. Combining these 
several individual probabilities, it will readily be perceived 
that not more than 
i_ v i v —1 — i _ 
of all the ejected lava masses, or about 3 in 5,000,000 of each 
possible size, would probably ever reach the earth as aero¬ 
lites ; nor is this an unsafe estimate. It is a very guarded 
oi^e, and the fraction % w oeo"o"o would be more likely to be 
correct. Now, can we regard it as probable that the moon 
has parted with so large an amount of matter as nearly, if 
not quite, two million times the combined mass of all the 
aerolites which have fallen to the earth? I think not. 
Even of those known to have fallen there are more than five 
hundred of various weights, one of them having a mass of 
thirty thousand pounds. The tokens of such a mass of 
gravitative matter as this would imply could not fail to be 
