FLOATING. 381 



ii. Strcugtltcniiifi the Bed of the Stream. 



The bed of a stream much less frequently requires artificial 

 improvement than the banks. This is, however, sometimes 

 requisite, in the case of mountain-torrents with stony beds, 

 and usually consists in blasting-away the rocks, and removing 

 stones which might otherwise cause holes to form behind them 

 in the bed of the stream, and thus catch the floating logs. The 

 best time for these operations is the autumn, or whenever the 

 water is lowest, and the stones removed from the stream may 



Fig. 223. 



be utilized to improve its banks. It is, however, easy to do too 

 much in the way of removing obstacles from the bed of a rapid 

 stream : for if a floating-channel be freed from all impeding 

 rocks and stones, which form so many natural weirs in its 

 course, the stream often becomes torrential, and its banks may 

 be broken and inundations or other disastrous consequences 

 ensue. 



Rapids may occur where the bed of a channel is narrow and 

 steep, and the stream runs between rocks in passing from a 

 higher stage in the valley to a lower one, and there is then 

 likely to be difficulty in floating the timber. If in such places 

 the bed be terraced (fig. 223), floating will be much expedited 

 by making a network of logs which is filled in with stones. 

 The blasting necessary in such a place is, however, so difficult 



