226 FRAGMENTS OF SCIENCE. 



level of which would be that of the col D, over which for 

 an indefinite period the lake would pour its water. 

 During this period the lowest Glen Roy road, which is 

 common also to Glen Glaster and Glen Spean, would be 

 formed. Finally, on the disappearance of the ice from 

 the lower part of Glen Spean the waters would flow 

 down their respective valleys as they do to-day. 



Reviewing our work, we find three considerable 

 steps to have marked the solution of the problem of the 

 Parallel Roads of Glen Roy. The first of these was taken 

 by Sir Thomas Dick-Lauder, the second was the pregnant 

 conception of Agassiz regarding glacier action, and the 

 third was the testing and verification of this concep- 

 tion by the very thorough researches of Mr. Jamieson. 

 No circumstance or incident connected with this dis- 

 course gives me greater pleasure than the recognition 

 of the value of these researches. They are marked 

 throughout by unflagging industry, by novelty and 

 acutcness of observation, and by reasoning power of a 

 high and varied kind. These pages had been returned 

 ' for press ' when I learned that the relation of Ben 

 Nevis and his colleagues to the vapour-laden winds of 

 the Atlantic had not escaped Mr. Jamieson. To him 

 obviously the exploration of Lochaber, and the develop- 

 ment of the theory of the Parallel Roads, has been a 

 labour of love. 



Thus ends our rapid survey of this brief episode 

 in the physical history of the Scottish hills, brief, 

 that is to say, in comparison with the immeasurable 

 lapses of time through which, to produce its varied 

 structure and appearances, our planet must have 

 passed. In the survey of such a field two things are 

 specially worthy to be taken into account the widen- 

 ing of the intellectual horizon and the reaction of ex- 

 panding knowledge upon the intellectual organ itself 



