260 



FRAGMENTS OF SCIENCE. 



highest shelf, until finally he reached a col, or water- 

 shed, looking into Glen Spey, and of precisely the same 

 elevation as the highest road of Glen Koy. 



PARALLEL ROADS OF GLEN ROY. 

 After a Sketch by SIR THOMAS DICK-LATJDEK. 



He then dropped down to the lowest of these roads, 

 and followed it towards the mouth of the glen. Its 

 elevation above the bottom of the valley gradually 

 increased ; not because the shelf rose, but because it 

 remained level while the valley sloped downwards. He 

 found this lowest road doubling round the hills at the 

 mouth of Glen Roy, and running along the sides of the 

 mountains which flank Glen Spean. He followed it 

 eastwards. The bottom of the Spean Valley, like the 

 others, gradually rose, and therefore gradually ap- 

 proached the road on the adjacent mountain-side. He 

 came to Loch La^gan, the surface of which rose almost 



