1868.] BABBAGE PAKALLEL KOADS. 273 



almost everything to running water and to scraping ice. They are 

 simply Catastrophists in a new dress. They attribute extravagant 

 power and stupendous effects to one form of force instead of to another. 



There is, indeed, one difference, and it is a difference in favour of 

 the older school of Catastrophists rather than of the younger — that 

 whereas there never could be any doubt of the adequacy of subter- 

 ranean force to produce the effects ascribed to it, there is the greatest 

 doubt of the adequacy of rain and ice to effect in any time, however 

 long, the stupendous changes ascribed to them by Mr. Geikie. On 

 the other hand, there is really nothing stupendous about those effects 

 when they are regarded in connexion with the known and visible 

 effects of subterranean force. The highest ranges of mountain we 

 have are, relatively to the circumference of the earth's crust, infi- 

 nitely smaller than the puckers on an orange-skin. 



The smallest amount of shrinkage, earthquake-waves and com- 

 motions of comparatively the gentlest and feeblest kind would 

 suffice to produce the tossings of the Highland Hills. Magnitude is 

 all relative. The store of Time and the store of Force may be re- 

 garded as both unlimited. But it does not follow that in accounting 

 for any given effect we are entitled to draw to an unlimited extent 

 either upon the one or upon the other. Extravagant demands may as 

 easily be made upon the one as upon the other. The inventions and 

 imaginations to which the extreme Glacialists resort are, beyond all 

 comparison, more violent than those which were common with the 

 old Convulsionists. Whole continents are built up upon the top of 

 the existing mountains, where there is no proof whatever that they 

 ever existed ; and then these continents are all ground down by ice, 

 or washed away by ordinary surf, and yet so that not a fragment 

 shall be left behind. I venture to believe that I shall have some 

 support from the great leaders of geological science, who, in power of 

 intellect, are still young among us, when 1 record my dissent from 

 the extravagant theories of the younger Glacialists. 



Febrfary 26, 1868. 

 David Homfray, Esq., Port Madoc, was elected a Fellow. 



The following communications were read : — 



1. Observations on the Parallel Roads o/Glen Koy. 

 By Charles Babbage, Esq., F.E.S. 

 (Communicated by the President.) 

 Many years have passed since I ^4sited the remarkable scenery of 

 the parallel roads of Glen Koy. Several explanations of their origin 

 have been given ; and my own view of the subject was, I appre- 

 hended, in accordance with the views of geologists. The recent pa- 

 per of Sir John Lubbock upon that subject shows that the causes 

 which have hitherto been assigned for their origin have not yet re- 

 ceived general assent. Under these circumstances, I think it desi- 

 rable to record the very simple explanation of their origin which had 

 satisfied my own mind. 



