ADDRESS SECTION A, B.A. 1876. 



causing earthquake-shocks, or by the roof breaking 

 quite through when very thin, so as to cause two 

 such hollows to unite, or the liquid of any of them 

 to flow out freely over the outer surface of the 

 earth, or by gradual subsidence of the solid owing 

 to the thermodynamic melting which portions of it 

 under intense stress must experience, according to 

 my brother's theory. The results which must 

 follow from this tendency seem sufficiently great 

 and various to account for all that we learn from 

 geological evidence of earthquakes, of upheavals 

 and subsidences of solid, and of eruptions of 

 melted rock." l 



Leaving altogether now the hypothesis of a 

 hollow shell filled with liquid, we must still face the 

 question, How much does the earth, solid through- 

 out, except small cavities or vesicles filled with 

 liquid, yield to the deforming (or tide-generating) 

 influences of sun and moon ? This question can 

 only be answered by observation. A single 



1 "Secular Cooling of the Earth," Transactions of the Royal 

 Society of Edinburgh, 1862 (W. Thomson), and Thomson and Tait's 

 Natural Philosophy, (), (//). 



