226 FRAGMENTS OF SCIENCE. 



fill all three glens, the 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 Eoy road, which is common also to Glen Glaster 

 and Glen Spean, would be formed. Finally, on the dis- 

 appearance of the ice from the lower part of Glen 

 Spean the waters would flow down their respective val- 

 leys as they do to-day. 



Eeviewing our work, we find three considerable 

 steps to have marked the solution of the problem of 

 the Parallel Eoads of Glen Eoy. 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 conception by the very thorough researches of 

 Mr. Jamieson. No circumstance or incident connected 

 with this discourse gives me greater pleasure than the 

 recognition of the value of these researches. They are 

 marked throughout by unflagging industry, by novelty 

 and acuteness of observation, and by reasoning power 

 of a high and varied kind. These pages had been re- 

 turned ( 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 

 development of the theory of the Parallel Eoads, 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- 



