FLOATING. 359 



logs and split pieces of hardwood is one and a half to three feet, 

 as then the workmen can always wade into the water to secure 

 the sunken wood. 



There is no necessity for any uniform fall in a stream, and 

 most streams used for floating timber vary greatly in this 

 respect. The best fall is o-J^ to tVj ^^ then the wood descends 

 rapidly, and is easily guided by the workmen ; there is then 

 little wear and tear owing to the pieces dashing together or 

 against rocks, which may also cause continual blocking of the 

 stream and necessitate severe labour to set the logs floating 

 again. Floating has, however, frequently to be undertaken with 

 a fall less, or much greater, than the above. In the latter case, 

 cascades have sometimes to be passed, and much timber is lost. 



Rafting can be done with a much less fall, and artificially con- 

 structed or improved rafting-streams have falls of only -=^ to 4-g^. 



The last point to be considered in the practicability of a stream 

 for floating timber consists in the possibility of artificially 

 damming its tributaries, so as to collect temporarily a much 

 greater head of water than it usually holds. 



There is much periodical variation in the amount of water in a 

 mountain-torrent, and a formidable, destructive torrent may be 

 sometimes seen where a few weeks later there will be merely a 

 little thread of water. In other cases a stream may be always 

 too low for floating, but by collecting the water of its tribu- 

 taries, enough water may be obtained to float down a sweep of logs. 



2. Improvement and Maintenance of Watercourses for Floating 

 Wood. 

 No watercourse is constantly fit for floating without some 

 artificial improvement, but all streams are not susceptible of the 

 same amount of improvement ; in many cases the low value 

 of the timber to be floated will not allow of much expenditure at 

 a profit in this direction, and sometimes, the forester has to put 

 up with the mere maintenance of the natural state of a stream. 

 Hence, the works on no two streams used for floating resemble one 

 another. In the following pages the most perfect methods of 

 improving and maintaining a floating-channel are described, 

 so that the forester may select what is practicable in any 

 particular case. 



