ool 
been originally confined beneath it; and thus a much greater 
amount of contraction may have taken place than mere cooling 
would account for. 
It is obvious that this reasoning will apply equally well to 
the case of a solid globe originally covered with a sufficiently 
deep layer of molten rock, which is the condition supposed by 
Sir W. Thomson to be the most probable, a view strongly 
supported by Dr Sterry Hunt’, and more in consonance with 
the rigidity considered requisite to obviate the production of 
internal tides. But at the same time it is to be remarked, that 
a highly fluid original condition of the interior may have lasted 
long after mountains commenced to be formed, and yet its 
condition need not continue such at the present time. 
February 2, 1874. 
The PRESIDENT (PROFESSOR BABINGTON) in the Chair. 
Mr F. A. PALEY gave a summary of a paper intended to 
shew that Thucydides must have been mistaken in describing 
what was really the city-wall of the Plateans, with its battle- 
ments and towers, as a temporary wall erected in three months 
by the besiegers. The paper contended that the Spartan army 
had got possession of and manned the city-wall, wishing to 
reduce the Platzans to the necessity of capitulating; and for 
this a political reason was given. Doubts were thrown on the 
account of a double wall and double moat, since the researches 
of modern travellers, which were quoted, did not bear out the 
statement, and no traces of either existed, though the ruins of the 
city-walls still remain in great part. It was shewn that ancient 
Greek cities had precisely such walls as Thucydides describes ; 
and his veracity in the account was impugned, on the supposition 
1 American Journal of Science, Vol. v. p. 264. 
26 
