40G WATEIL-TKANSroKT. 



Once the wood has been carried down to the main floating' 

 channel, the sweep of lof?s now becomes the principal sweep and 

 floats on to the boom. In the case of larger brooks and rivers, 

 the wood is left to itself, but if the water is shallow, assistance 

 must still be afforded from reservoirs. 



Usually the principal reservoirs of the subsidiary streams, if 

 they help one another, and flow one after the other into the 

 main stream, greatly assist in floating the principal sweep. 

 Experience shows how long a flood from a reservoir takes to 

 reach the main stream, and this period is chosen for the in- 

 terval between the opening of the sluice-gates of neighbouring 

 reservoirs. In long and weak floating-channels the reservoirs 

 of the tributaries are not sufficient to maintain high water in 

 the main stream, and in such cases reservoirs should be pro- 

 vided along the main channel. In flouting a sweep great care 

 must be taken that the reservoirs on the subsidiary and main 

 channels work well together. As soon as the reservoirs of the 

 tributaries are again full, more wood is launched and floated, 

 and this continues daily until all the wood has been launched 

 and has gradually reached the booms, when it is either collected 

 in tanks, or taken out of the water, according to the nature of 

 the boom. 



Whenever a floating-clumnel passes through a lake the wood 

 must be stopped as it enters the lake and towed across it. 

 Everywhere for this purpose light coniferous logs are used, 

 which are bound-together by iron rings, or withes, and thus 

 form a long floating girdle which may be used to surround the 

 wood in the lake and keep it together. With this object, the 

 chain of logs is placed in an arc before the entrance to the lake, 

 and as soon as it has enclosed as many logs as possible, its ends 

 are joined. The raft thus formed is then borne to the other end 

 of the lake, either by help of a favourable wind, by beasts or 

 niiinual labour ; the chain is then opened and the logs floated 

 further down the stream. 



Favourable weather is necessary for this crossing to be 

 effected ; storms not unfrcquently break-up these rafts and 

 scatter the logs over the surface of the lake, so that great 

 expense is incurred in collecting them. On the Pacific coast 

 of North America, and also in Norway and Sweden where it 



