Correspondence. 189 
" It was," he said, " a special characteristic of this philosophical sys- 
tem that it sought ia the changes now in progress on the earth's surface 
an explanation of those which occurred in ancient times. Its founder 
refused to invent causes or modes of operation, for those with which he 
was familiar seemed to him adequate to solve the problems with which 
he attempted to deal. Xowhere was the profoundness of his insight 
more astonishing than in the clear, definite way in which he proclaimed 
and reiterated his doctrine that every part of the surface of the conti- 
nents, from mountain-top to sea-shore, is continually undergoing decay, 
and is thus slowly travelling to the sea. He saw that no sooner will the 
sea-floor be elevated into new land than it must necessarily become a 
prey to this universal and unceasing degradation. He perceived that as the 
transport of disintegrated material is carried on chiefly by running water, 
rivers must slowly dig out for themselves the channels in which they 
flow, and thus that a system of valleys radiating from the water-parting 
of a country must necessarily result from the descent of the btreams 
from the mountain crests to the sea. He discerned that this -ceaseless 
and wide spreading decay would eventually lead to the entire demolition 
of the dry land, but he contended that from time to time this catastrophe 
is prevented by the operation of the underground forces, whereby new 
continents are upheaved from the bed of the ocean." 
"But despite his firm grasp of general principles and his mastery of 
the minutest details, he had acquired a literary style which was singu- 
larly unattractive. Fortunately for his fame as well as for the cause of 
science, his devoted friend and disciple, Playfair, at once set himself to 
draw up an exposition of Hutton's views. After Ave years of labor on 
this task, there appeared the classic ' Illustrations of the Huttonian 
Theory,' a work which for luminous treatment and graceful diction 
stands still without a rival in English geological literature." 
Sir A. Geikie then rapidly reviewed the progress of these new opin- 
ions and sketched the various objections, scientitic and theological, 
which they had met, passing on to the experimental work of Sir James 
Hall, and the stratigrapbical investigations of William Smith, the 
" father of British Stratigraphy," and dwelling, as was seemly and cour- 
teous, on the great share that Edinburgh and Scotland had taken in the 
progress of the new science. Passing rapidly over the long and bitter 
conflict between the Plutonists and the Neptunists, which was mainly 
waged in the north, he proceeded to the discussion of what may be re- 
garded as the central scientific subject of his address — Uniformity versus 
Catastrophe. "Though," he said, " Hutton and Playfair believed in pe- 
riodical catastrophes, and indeed required these in order to renew and 
preserve the habitable condition of our planet, their successors gradu- 
ally came to view with repugnance any appeal to abnormal and espec- 
ially to violent manifestations of terrestrial vigor, and even persuaded 
themselves that such slow and comparatively gentle action as had been 
witnessed by man could alone be recognized in the evidence from which 
geological history must be compiled. Well do I remember in my own 
boyhood what a cardinal article of faith this prepossession had become: 
