by Sedimentary Loading and Recurrent Expansion. 495 



Answers to some Objections. 



The object of this outline of my theory is to focus its 

 salient points, as many of my critics for some reason or other 

 have failed to grasp them. What they criticise is frequently 

 not my theory, but some rather vague notion called the 

 " Herschel-Babbage " theory. What is exactly covered by 

 this description I have a difficulty in ascertaining. On the 

 other hand, one writer calls Mr. 0. Fisher's theory, with 

 which mine has no analogy, the a Herschel-Babbage " theory. 

 I trust I shall give no offence by repudiating this labelling 

 and claiming the theory as my own. 



Neither Herschel, Scrope, nor Babbage ever advanced so 

 far as to elaborate what could be justly called a theory of 

 Mountain-Building. They gave to the world some fruitful 

 suggestions, and acute reasoning thereon, which have been of 

 considerable use to a succession of speculators in Geological 

 Physics, and to myself among the rest *. One of the most 

 frequently urged objections to my theor} r is the supposed 

 inadequacy of expansion by rise of temperature to account 

 tor the excessive folding some mountain-chains have under- 

 gone, linear expansion only being considered. My reply to 

 this is that even linear expansion alone places at our disposal 

 more lateral movement than any other theory. It is true 

 that those speculators who have invoked tangential thrust 

 through the assumed shrinking of the Earth's nucleus, have 

 had at their command any amount of lateral movement their 

 imagination liked to draw upon, hence the simplicity and 

 success of the theory — for a time. It has, however, been 

 shown pretty clearly that the Bank upon which these cheques 

 have been drawn is one of very limited liability f? and quite 

 unequal to honouring them. 



Prof. Hutton, in his very able address to Section C of the 

 Melbourne Meeting of the Australasian Association for the 

 Advancement of Science, gives an excellent resume of the 

 various hypotheses that have been suggested to account for 

 Mountain-Budding. 1 confidently appeal to his description 

 to show that, omitting the theory of secular contraction of the 

 Earth's nucleus, which he disposes of very effectually, none of 

 the suggestions, theories, or hypotheses except the one I 



* Until after my work was published I had read nothing of this but 

 what was contained in Ly ell's ' Principles ' and letters, and Babbage's 

 paper, read before the Geological Society in 1834, nor had I read Scrope's 

 views. 



t See ELutton's examination of this theory in the Address referred to. 



