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CORRESPONDENCE. 
*** The Editor does not hold himself responsible for statements of fa£s or 
opinions expressed in Correspondence, or in Articles bearing the signature 
of their respective authors. 
PROFESSOR BALL’S “GLIMPSE THROUGH THE 
CORRIDORS OF TIME.” 
To the Editor of the Journal of Science . 
Sir, — In a ledture delivered in Birmingham, Prof. Ball, Astro- 
nomer Royal for Ireland, recently announced his discovery, by 
mathematical processes, that the Moon is the child of the Earth. 
At first, he says, the Moon revolved round its primary very near 
to it, but in the course of countless millions of ages it has gra- 
dually receded from it, and is still receding. This, I need hardly 
remind your readers, is the conclusion arrived at in my book on 
“ The Constitution of the Earth,” * and which has been further 
expounded in several articles in your pages. (See “Journal of 
Science ” for August, 1880, May, 1881, and June, 1881.) “ At the 
time of its birth,” says Prof. Ball, “ the Earth was not as we see 
it now, clothed with vegetation and teeming with animal life. It 
was a huge inorganic mass, too hot for life, perhaps hot enough 
to be soft or viscid, if not actually molten. The offspring was 
what might be expedted from such a parent. It was also a rude 
inorganic mass. Time has wrought wondrous changes in both 
parent and child. Time has transformed the Earth into an abode 
of organic life. It has transformed the Earth’s offspring into 
our silvery Moon.” The Professor then goes on to describe the 
way in which these changes have been brought about, in which 
he declares that he is guided “ by a light which cannot deceive. 
It is the light of mathematical reasoning.” 
Mr. G. H. Darwin has been making the phenomena of tides a 
special study, and he has arrived at the conclusion that the solid 
earth itself is in constant motion, as the result of tidal influence. 
The Sun produces tides as well as the Moon, but the solar tides 
* The Constitution of the Earth ; being an Interpretation of the Laws of 
God in Nature by which the Earth and its Organic Life have been derived 
from the Sun by a Progressive Development. London : George Bell and Sons. 
