EFFECTS OF DRAINAGE. 23 



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 

 insects upon which trout feed is materially lessened, 

 and at the same time the number and size of trout, 

 which, as has just been stated, depends in a great 

 measure upon the quantity of food. If drainage, 

 for which there is no remedy, has such an injurious 

 effect, there is the more necessity for looking after 

 the causes which might be stopped ; and the worst 

 of these are the manufactories, bleachfields, etc., 

 which are so thickly studded along the banks of our 

 southern streams, and which send their dyes and 

 other deleterious refuse straight into the streams, 

 causing sad havoc. When we mentioned this in 

 our first edition, the Border Advertiser came down 



