24 FRESH- WATER TROUT. 



for, and the most prejudicial of these is the drain- 

 age of the land, more particularly of the hill- 

 pastures for sheep. So long as drainage was 

 confined to the river's banks, its effects were not 

 so observable ; but now that it has extended to 

 the recesses of the mountains, whence most of our 

 rivers receive nine-tenths of their water, and every 

 hill, glen, and moor is drained, it tells severely 

 upon the streams and their inhabitants. The 

 water, which used to find its way to the rivers 

 gradually, keeping them large and full for a con- 

 siderable time, is now conducted to them very 

 soon after the rain falls, and runs off in a day or 

 two, leaving them clear and dwindled till the next 

 flood. 



Several old residents on Tweedside have assured 

 us, that fifty years ago, when there was a flood? 

 Tweed continued the dark porter colour, so highly 

 prized by anglers, for a week or more, and then 

 ran clear but pretty full. Now the flood is very 

 heavy for the first day or two, and then falls rapidly, 

 in three or four days becoming quite clear, and for 

 weeks scarcely half the size of what it used to be 

 when at its smallest. 



It is supposed that the heavy floods we now 

 have shift the gravel, and carry off a large quantity 

 of the spawn of the trout, and also of the eggs of 

 aquatic insects. Then, again, when the waters are 

 very small, the eggs of aquatic insects are left dry, 

 and their vitality destroyed, so that the number of 



