Geological Society. 399 



it had risen to 2f tons a slight report was heard in the press, indi- 

 cating the fracture of one of the thermometers. On examining the 

 contents of the press afterwards it was found that No. 2 was broken ; 

 the others were uninjured. The broken thermometer was the earliest 

 constructed upon the plan now proposed, and it was consequently not 

 quite so well finished as subsequent practice has secured for those of 

 later construction. The results of the trial under the higher pres- 

 sures showed an increase in the amount of compression experienced 

 by the unprotected instruments rising in one instance to as much as 

 1 1°'5 F. With the protected instruments the rise did not exceed 1°'5, 

 due, as before, to the heat evolved from the water by its compression. 

 A pressure of 3 tons, it may be observed, would be equal to that 

 of 448 atmospheres of 15 lb. upon the square inch ; and if it be as- 

 sumed that the diminution in bulk of water under compression con- 

 tinues uniformly at the rate of 4/ millionths of its bulk for each ad- 

 ditional atmosphere, the reduction in bulk of water under a pressure 

 of 3 tons upon the square inch will amount to about jj of its ori- 

 ginal volume. This probably is too high an estimate, as the rate 

 of diminution would most likely decrease as the pressure increases. 



GEOLOGICAL SOCIETY. 

 [Continued from p. 322.] 



February 24th, 1869,— Prof. T. H. Huxley, LL.D„ F.R.S., 



President, in the Chair. 



The following communication was read : — 



t( On the British. Postglacial Mammalia." By W. Boyd Daw- 

 kins, Esq., M.A., F.B.S., F.G.S. 



The author stated that the Postglacial or Quaternary Mammalia 

 of Englard and Wales amounted to 47. Of these only 15 are found 

 in Caves and not in Eiver deposits, whilst out of 31 found in the 

 latter, only 1 does not occur in caves ; hence the author inferred 

 that the Cave and River deposits are palseontologically synchronous. 

 In Scotland, remains of Mammalia have occurred only in five places, 

 and in Ireland only in two places, in beds of Postglacial age. The 

 author ascribed this unequal distribution to the long continuance of 

 subaerial glaciation in Ireland, Scotland, and North Wales. 



The author then compared the Postglacial with, the Preglacial 

 Mammalia. The British species of the latter are : — 



Ursus arveraensis. 



spelcsus?. 



Sorex. 



Mygale moschata. 

 Talpa europcea. 

 Cervus mcgaceros ? 



caprcolus. 



elaphus. 



Sedgwickii. 



Ardeus. 



Bos primigenius. 

 Hippopotamus major. 

 Equus fossilis. 

 BMnoceros megarhinus. 



Etruscus. 



Elephas antiquus. 



meridionalis. 



Arvicola amphibia. 

 Castor fiber. 

 Trogontlierium Cuvieri. 



