BRITISH ASSOCIATION MEETING. 



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BRITISH ASSOCIATION MEETING. 



The British Association Meeting was held this year at Manchester, and was 

 marked by an nnusualJy large attendance of members and associates. 



The President's Address. 



The President, Mr. Pairbairn, in his opening address, dwelt but slightly on 

 the progress of Geology — the chief portion of his speech being devoted, as 

 was to be expected, to manufactures and applied mechanics. We give that 

 part of his speech which relates to our science. 



" It is little more than half a century since Geology assumed the distinctive 

 character of a science. Taking into consideration the aspects of nature in 

 different epochs of the history of the earth, it has been found that the study 

 of the changes at present going on in the world around us enable us to under- 

 stand the past revolutions of the globe, and the conditions and circumstances 

 under which strata have been formed and organic remains embedded and pre- 

 served. The geologist has increasingly tended to believe that the changes 

 which have taken place on the face of the globe, from the earliest times to the 

 present, are the result of agencies still at work. But whilst it is his high 

 office to record the distribution of life in past ages and the evidence of physical 

 changes in the arrangement of land and water, his results hitherto have indi- 

 cated no traces of its beginning, nor have they afforded evidence of the time 

 of its future duration. Geology has been indebted for this progress very largely 

 to the investigations of Sedgwick and the writings of Sir Charles Lyell. 



" As an example of the application of Geology to the practical uses of life, I 

 may cite the discovery of the gold fields of Australia, which might long have 

 remained hidden, but for the researches of Sir Roderick Murchison in the 

 Ural Mountains on the geological position of the strata from which the Russian 

 gold is obtained. Prom this investigation he was led by inductive reasoning 

 to believe that gold would be found in similar rocks, specimens of which had 

 been sent him from Australia. The last years of the active life of this dis- 

 tinguished geologist have been devoted to the re-examination of the rocks of 

 his native Highlands of Scotland. Applying to them those principles of classi- 

 fication which he long since established, he has demonstrated that the crystal- 

 line limestones and quartz-rocks which are associated with mica-schists, &c, 

 belong by their embedded organic remains to the Lower Silurian Rocks. 

 Descending from this well-marked horizon, he shows the existence beneath all 

 such fossiliferous strata of vast masses of sandstone and conglomerate of 

 Cambrian age; and, lastly, he has proved the existence of a fundamental 

 Gneiss, on which all the other rocks repose, and which, occupying the North- 

 Western Hebrides and the west coasts of Sutherland and Ross, is the oldest 

 rock-formation in the British Isles, it being unknown in England, Wales, or 

 Ireland. 



" It is well known that the temperature increases, as we descend through the 

 earth's crust, from a certain point near the surface, at which the temperature 

 is constant. In various mines, borings, and Artesian wells, the temperature 

 has been found to increase about 1° Pahrenheit for every sixty or sixty-five feet 

 of descent. In some carefully conducted experiments during the sinking of the 

 Dukinfield Deep Mine, — one of the deepest pits in this country, — it was found 

 that a mean increase of about 1° in seventy-one feet occurred. If we take 

 the ratio thus indicated, and assume it to extend to much greater depths, we 

 should reach at two and a half miles from the surface strata at the temperature 

 of boiling water ; and at depths of about fifty or sixty miles the temperature 



