Address of Sir Wm. Thomson at the Glasgow Meeting. 347 
process must go on until the sunk portions of crust build up 
from the bottom a sufficiently close-ribbed skeleton or frame, 
to allow fresh incrustations to remain bridging across. the now 
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.”* 
aving altogether now the hypothesis of a hollow shell 
ing influence of sun or moon. The effe 
on the plumb-line of the lunar tide-generating influence is to 
ZO 
overhead, and is greatest in either direction when the moon is 
above or below the horizon. When this greatest value 1s 
Teached, the plummet is drawn from its mean position through 
* 
“Secular Cooling of the Earth.” Transactions of the Royal Society of Ed- 
ee (W. Thomson), and Thomson and Tait’s * Natural Philosophy,” 
* 
