A2JNIVEIISAET ADDRESS OF THE PEESIDEyT. TTXl 



discussions in the admirable Eeport to tlie British Assodation on the 

 Geological Theories of Elevation and Earthquakes. 



In the fourth Yolume of our Journal he applied his results on 

 these subjects in a paper " On the Elevation and Denudation of the 

 District of the Lakes of Cumberland, and Westmoreland." This was 

 followed by a paper, in the seventh volume, " On the Geological Struc- 

 ture of the Wealden district, and of the Bas Eoulonnais." 



The Wollaston Palladium lledal was, in 1850, awarded to Mr. 

 Hopkins, in recognition of the value of his researches on the appli- 

 cation of mathematics and physics to geology. 



In 1851 he read a paper to the British Association " On the Dis- 

 tribution of Granitic Blocks from Ben Cruachan," a subject which 

 he enlarged upon before this Society (Quart. Joum. vol. viii. p. 28). 



In the years 1851 and 1852 he was President of our Society. 

 His first Address was in great part on the Drift and the phenomena 

 of its distribution, terminated by excellent observations on the theory 

 of ^progression in organic nature, as well as in the inorganic matter 

 of our planet. The second Address placed before us, in a clear and 

 fairly stated aspect, M. Elie de Beaumonf s theory of the Elevation 

 of Mountain- chains ; and, by an elaborate examination into its con- 

 formity with observed facts, he showed the imperfect evidence on 

 which it depends, and the necessity for great caution and reserve in 

 accepting it in any degree of generality approaching that which its 

 author would assign to it. 



One of the most important physical treatises ever read before this 

 Society was that by Mr. Hopkins in 1851, " On the Causes which 

 may have produced Changes in the Earth's Superficial Temperature." 

 In this treatise he considered, first, the influence of the earth's iuter- 

 nal heat, and of the heat radiating from external bodies, on the earth's 

 superficial temperature ; and, secondly, the influence of various con- 

 figurations of land and sea and of oceanic currents. The very small 

 part (-^ of a degree Fahrenheit) of the earth's present superficial 

 temperature which is due to internal heat proves how in future no 

 appreciable change of climate can result from the refrigeration of the 

 globe, and how, looking back iuto the past, we shall require an enor- 

 mous period to account for even a very minute difference of mean 

 temperature. Xow mathematical investigation shows that this effect 

 of the internal heat on the superficial temperature bears a constant 

 ratio to the rate of increase which is observed in depth. Conse- 

 quently, knowing this ratio at the present time, we can ascertaiu the 

 rate at which the temperature must have increased in descending at 

 any past geological epoch at which the effect of the earth's internal 

 heat was of any assigned amount. Thus when the superficial tem- 

 perature was raised 1° E. by this means, or twenty times the present 

 amount of this increment, the descending rate of increase must have 

 been twenty times as great as at present, about 20° E. for every 

 60 feet ; and if the superficial temperature were thus raised about 

 10° F., the temperature at the depth of 60 feet would, according to 

 the same law, exceed 200° F., and all but surface springs would be 

 springs of boiling water. The incompatibility of such conditions 



